Fix VSCode integrated terminal forward delete word

In VSCode 1.62.2, alt+delete (forward delete or forward kill word) began
behaving like the enter key, sending commands instead of deleting words.
This was occurring with both Bash and Zsh.

Diagnostics:

- Command Palette -> Enable escape sequence logging
- Command Palette -> Toggle developer tools
- Open the developer tools console
- Start typing commands into the terminal

Solution:

Add a keybinding to trigger `workbench.action.terminal.sendSequence`
with `\u001bd` when `alt+delete` key events occur.

`\u001bd` is a JavaScript Unicode escape sequence:

- `\u` demarcates the sequence
- `001b` is the escape sequence
- `d` is an additional modifier

VSCode recognizes `\u001bd` as `alt+d`, which is forward delete.

microsoft/vscode#95802
https://github.com/microsoft/vscode/blob/1.62.2/src/vs/workbench/contrib/terminal/browser/terminal.contribution.ts#L167-L171
https://code.visualstudio.com/docs/editor/integrated-terminal
https://github.com/microsoft/vscode/wiki/Terminal-Issues
https://mathiasbynens.be/notes/javascript-escapes

vscode/User/keybindings.json

@@ -65,6 +65,13 @@
     "command": "workbench.action.terminal.focusPrevious",
     "when": "terminalFocus"
   },
+  // Fix terminal forward delete word
+  {
+    "key": "alt+delete",
+    "command": "workbench.action.terminal.sendSequence",
+    "args": { "text": "\u001bd" },
+    "when": "terminalFocus"
+  },
   // Go to definition
   {
     "key": "ctrl+cmd+g",