doc: remove problematic auto-linking of curl man pages

The only instance of curl man page linking is in repl.md and it is
explicit. The magic autolinking in html.js creates a superfluous empty
link. Remove it.

Before, two adjacent links generated, with the first one having no text:

```html
<a href="https://curl.haxx.se/docs/manpage.html"></a>
<a href="https://curl.haxx.se/docs/manpage.html"><code>curl(1)</code></a>
```

After, just one link:

```html
<a href="https://curl.haxx.se/docs/manpage.html"><code>curl(1)</code></a>
```

PR-URL: nodejs#35174
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ben Coe <bencoe@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

Author: Trott

doc/api/repl.md

@@ -745,7 +745,7 @@ For an example of running a "full-featured" (`terminal`) REPL over
 a `net.Server` and `net.Socket` instance, see:
 <https://gist.github.com/TooTallNate/2209310>.
 
-For an example of running a REPL instance over [curl(1)][], see:
+For an example of running a REPL instance over [`curl(1)`][], see:
 <https://gist.github.com/TooTallNate/2053342>.
 
 [ZSH]: https://en.wikipedia.org/wiki/Z_shell
@@ -761,5 +761,5 @@ For an example of running a REPL instance over [curl(1)][], see:
 [`util.inspect()`]: util.html#util_util_inspect_object_options
 [`reverse-i-search`]: #repl_reverse_i_search
 [TTY keybindings]: readline.html#readline_tty_keybindings
-[curl(1)]: https://curl.haxx.se/docs/manpage.html
+[`curl(1)`]: https://curl.haxx.se/docs/manpage.html
 [stream]: stream.html

tools/doc/html.js

@@ -126,7 +126,6 @@ function preprocessText({ nodeVersion }) {
 
 // Syscalls which appear in the docs, but which only exist in BSD / macOS.
 const BSD_ONLY_SYSCALLS = new Set(['lchmod']);
-const HAXX_ONLY_SYSCALLS = new Set(['curl']);
 const MAN_PAGE = /(^|\s)([a-z.]+)\((\d)([a-z]?)\)/gm;
 
 // Handle references to man pages, eg "open(2)" or "lchmod(2)".
@@ -143,9 +142,6 @@ function linkManPages(text) {
         return `${beginning}<a href="https://www.freebsd.org/cgi/man.cgi` +
           `?query=${name}&sektion=${number}">${displayAs}</a>`;
       }
-      if (HAXX_ONLY_SYSCALLS.has(name)) {
-        return `${beginning}<a href="https://${name}.haxx.se/docs/manpage.html">${displayAs}</a>`;
-      }
 
       return `${beginning}<a href="http://man7.org/linux/man-pages/man${number}` +
         `/${name}.${number}${optionalCharacter}.html">${displayAs}</a>`;