⏪️ Revert unintended README changes (MarlinFirmware#26967)

* Revert all the changes that went in with the unit test framework
This restored broken links and other changes. Restoring to the prior revision seems the most appropriate action until the intentions of those file changes are known.
---------

Co-authored-by: Jason Smith <jason.inet@gmail.com>

Author: 2 people

README.md

@@ -39,16 +39,16 @@ To build and upload Marlin you will use one of these tools:
 
 Marlin is optimized to build with the **PlatformIO IDE** extension for **Visual Studio Code**. You can still build Marlin with **Arduino IDE**, and we hope to improve the Arduino build experience, but at this time PlatformIO is the better choice.
 
-## 8-Bit AVR Boards
-
-We intend to continue supporting 8-bit AVR boards in perpetuity, maintaining a single codebase that can apply to all machines. We want casual hobbyists and tinkerers and owners of older machines to benefit from the community's innovations just as much as those with fancier machines. Plus, those old AVR-based machines are often the best for your testing and feedback!
-
 ## Hardware Abstraction Layer (HAL)
 
 Marlin includes an abstraction layer to provide a common API for all the platforms it targets. This allows Marlin code to address the details of motion and user interface tasks at the lowest and highest levels with no system overhead, tying all events directly to the hardware clock.
 
 Every new HAL opens up a world of hardware. At this time we need HALs for RP2040 and the Duet3D family of boards. A HAL that wraps an RTOS is an interesting concept that could be explored. Did you know that Marlin includes a Simulator that can run on Windows, macOS, and Linux? Join the Discord to help move these sub-projects forward!
 
+## 8-Bit AVR Boards
+
+A core tenet of this project is to keep supporting 8-bit AVR boards while also maintaining a single codebase that applies equally to all machines. We want casual hobbyists to benefit from the community's innovations as much as possible just as much as those with fancier machines. Plus, those old AVR-based machines are often the best for your testing and feedback!
+
 ### Supported Platforms
 
   Platform|MCU|Example Boards
@@ -71,9 +71,22 @@ Every new HAL opens up a world of hardware. At this time we need HALs for RP2040
   [Teensy 4.1](https://www.pjrc.com/store/teensy41.html)|ARM® Cortex-M7|
   Linux Native|x86/ARM/etc.|Raspberry Pi
 
+## Submitting Patches
+
+Proposed patches should be submitted as a Pull Request against the ([bugfix-2.1.x](https://github.com/MarlinFirmware/Marlin/tree/bugfix-2.1.x)) branch.
+
+- This branch is for fixing bugs and integrating any new features for the duration of the Marlin 2.1.x life-cycle.
+- Follow the [Coding Standards](https://marlinfw.org/docs/development/coding_standards.html) to gain points with the maintainers.
+- Please submit Feature Requests and Bug Reports to the [Issue Queue](https://github.com/MarlinFirmware/Marlin/issues/new/choose). Support resources are also listed there.
+- Whenever you add new features, be sure to add tests to `buildroot/tests` and then run your tests locally, if possible.
+  - It's optional: Running all the tests on Windows might take a long time, and they will run anyway on GitHub.
+  - If you're running the tests on Linux (or on WSL with the code on a Linux volume) the speed is much faster.
+  - You can use `make tests-all-local` or `make tests-single-local TEST_TARGET=...`.
+  - If you prefer Docker you can use `make tests-all-local-docker` or `make tests-all-local-docker TEST_TARGET=...`.
+
 ## Marlin Support
 
-The Issue Queue is reserved for Bug Reports and Feature Requests. Please use the following resources for help with configuration and troubleshooting:
+The Issue Queue is reserved for Bug Reports and Feature Requests. To get help with configuration and troubleshooting, please use the following resources:
 
 - [Marlin Documentation](https://marlinfw.org) - Official Marlin documentation
 - [Marlin Discord](https://discord.gg/n5NJ59y) - Discuss issues with Marlin users and developers
@@ -82,48 +95,59 @@ The Issue Queue is reserved for Bug Reports and Feature Requests. Please use the
 - Facebook Group ["Marlin Firmware for 3D Printers"](https://www.facebook.com/groups/3Dtechtalk/)
 - [Marlin Configuration](https://www.youtube.com/results?search_query=marlin+configuration) on YouTube
 
-## Contributing Patches
+## Contributors
 
-You can contribute patches by submitting a Pull Request to the ([bugfix-2.1.x](https://github.com/MarlinFirmware/Marlin/tree/bugfix-2.1.x)) branch.
+Marlin is constantly improving thanks to a huge number of contributors from all over the world bringing their specialties and talents. Huge thanks are due to [all the contributors](https://github.com/MarlinFirmware/Marlin/graphs/contributors) who regularly patch up bugs, help direct traffic, and basically keep Marlin from falling apart. Marlin's continued existence would not be possible without them.
 
-- We use branches named with a "bugfix" or "dev" prefix to fix bugs and integrate new features.
-- Follow the [Coding Standards](https://marlinfw.org/docs/development/coding_standards.html) to gain points with the maintainers.
-- Please submit Feature Requests and Bug Reports to the [Issue Queue](https://github.com/MarlinFirmware/Marlin/issues/new/choose). See above for user support.
-- Whenever you add new features, be sure to add one or more build tests to `buildroot/tests`. Any tests added to a PR will be run within that PR on GitHub servers as soon as they are pushed. To minimize iteration be sure to run your new tests locally, if possible.
-  - Local build tests:
-    - All: `make tests-config-all-local`
-    - Single: `make tests-config-single-local TEST_TARGET=...`
-  - Local build tests in Docker:
-    - All: `make tests-config-all-local-docker`
-    - Single: `make tests-config-all-local-docker TEST_TARGET=...`
-  - To run all unit test suites:
-    - Using PIO: `platformio run -t test-marlin`
-    - Using Make: `make unit-test-all-local`
-    - Using Docker + make: `maker unit-test-all-local-docker`
-  - To run a single unit test suite:
-    - Using PIO: `platformio run -t marlin_<test-suite-name>`
-    - Using make: `make unit-test-single-local TEST_TARGET=<test-suite-name>`
-    - Using Docker + make: `maker unit-test-single-local-docker TEST_TARGET=<test-suite-name>`
-- If your feature can be unit tested, add one or more unit tests. For more information see our documentation on [Unit Tests](test).
+## Administration
 
-## Contributors
+Regular users can open and close their own issues, but only the administrators can do project-related things like add labels, merge changes, set milestones, and kick trolls. The current Marlin admin team consists of:
 
-Marlin is constantly improving thanks to a huge number of contributors from all over the world bringing their specialties and talents. Huge thanks are due to [all the contributors](https://github.com/MarlinFirmware/Marlin/graphs/contributors) who regularly patch up bugs, help direct traffic, and basically keep Marlin from falling apart. Marlin's continued existence would not be possible without them.
+<table align="center">
+<tr><td>Project Maintainer</td></tr>
+<tr><td>
+
+ 🇺🇸  **Scott Lahteine**
+       [@thinkyhead](https://github.com/thinkyhead)
+       [<kbd>  Donate 💸  </kbd>](https://www.thinkyhead.com/donate-to-marlin)
+
+</td><td>
+
+ 🇺🇸  **Roxanne Neufeld**
+       [@Roxy-3D](https://github.com/Roxy-3D)
+
+ 🇺🇸  **Keith Bennett**
+       [@thisiskeithb](https://github.com/thisiskeithb)
+       [<kbd>  Donate 💸  </kbd>](https://github.com/sponsors/thisiskeithb)
+
+ 🇺🇸  **Jason Smith**
+       [@sjasonsmith](https://github.com/sjasonsmith)
+
+</td><td>
 
-## Project Leadership
+ 🇧🇷  **Victor Oliveira**
+       [@rhapsodyv](https://github.com/rhapsodyv)
 
-Name|Role|Link|Donate
-----|----|----|----
-🇺🇸 Scott Lahteine|Project Lead|[[@thinkyhead](https://github.com/thinkyhead)]|[💸 Donate](https://www.thinkyhead.com/donate-to-marlin)
-🇺🇸 Roxanne Neufeld|Admin|[[@Roxy-3D](https://github.com/Roxy-3D)]|
-🇺🇸 Keith Bennett|Admin|[[@thisiskeithb](https://github.com/thisiskeithb)]|[💸 Donate](https://github.com/sponsors/thisiskeithb)
-🇺🇸 Jason Smith|Admin|[[@sjasonsmith](https://github.com/sjasonsmith)]|
-🇧🇷 Victor Oliveira|Admin|[[@rhapsodyv](https://github.com/rhapsodyv)]|
-🇬🇧 Chris Pepper|Admin|[[@p3p](https://github.com/p3p)]|
-🇳🇿 Peter Ellens|Admin|[[@ellensp](https://github.com/ellensp)]|[💸 Donate](https://ko-fi.com/ellensp)
-🇺🇸 Bob Kuhn|Admin|[[@Bob-the-Kuhn](https://github.com/Bob-the-Kuhn)]|
-🇳🇱 Erik van der Zalm|Founder|[[@ErikZalm](https://github.com/ErikZalm)]|[💸 Donate](https://flattr.com/submit/auto?user_id=ErikZalm&url=https://github.com/MarlinFirmware/Marlin&title=Marlin&language=&tags=github&category=software)
+ 🇬🇧  **Chris Pepper**
+       [@p3p](https://github.com/p3p)
+
+🇳🇿  **Peter Ellens**
+       [@ellensp](https://github.com/ellensp)
+       [<kbd>  Donate 💸  </kbd>](https://ko-fi.com/ellensp)
+
+</td><td>
+
+ 🇺🇸  **Bob Kuhn**
+       [@Bob-the-Kuhn](https://github.com/Bob-the-Kuhn)
+
+ 🇳🇱  **Erik van der Zalm**
+       [@ErikZalm](https://github.com/ErikZalm)
+
+</td></tr>
+</table>
 
 ## License
 
 Marlin is published under the [GPL license](/LICENSE) because we believe in open development. The GPL comes with both rights and obligations. Whether you use Marlin firmware as the driver for your open or closed-source product, you must keep Marlin open, and you must provide your compatible Marlin source code to end users upon request. The most straightforward way to comply with the Marlin license is to make a fork of Marlin on Github, perform your modifications, and direct users to your modified fork.
+
+While we can't prevent the use of this code in products (3D printers, CNC, etc.) that are closed source or crippled by a patent, we would prefer that you choose another firmware or, better yet, make your own.