Add support for references when no [] exists

[ghost]

This PR fixes #141285

Code has been updated with the main branch and I have personally reviewed it.

Changes

Alters the regex to match [...] and [...][...]. Treats [...] as if it's the same as [...][].

Testing

On the feature branch:

1. Create a new markdown file.
2. Add in some references. For example:

   [Works]
   [Works][]
   [Works][Works]
   [Still Works][Works]
   
   [Does Not Work]
   [Does Not Work][]
   [Does Not Work][DoesNotWork]
   [Works][DoesNotWork] Jokes
   
   [Works]
   
   [Works]: https://microsoft.com

3. Make sure that the links that you'd expect to work continue to work, both in the editor display and the preview.
   • Expected behavior in editor: Ctrl-Click (or Cmd-Click on Mac) brings cursor to reference.
   • Expected behavior in preview: References turn blue and link to their targets.
   • Preview can be opened via running Markdown: Open Preview from the Command Palette.

Expected Output

[mjbvz]

Thanks for taking a look! Can you please also add tests for this:

vscode/extensions/markdown-language-features/src/test/documentLinkProvider.test.ts

Line 15 in 7ccb868

const testFile = vscode.Uri.joinPath(vscode.workspace.workspaceFolders![0].uri, 'x.md');

In the tests, also try adding test for potential edge cases or false positives where link detection should not occur

I'm also inclined to say that the link detection should not kick in for [Works]: https://microsoft.com. We already highlight the destination link in that case and highlighting the link id itself doesn't strike me as useful here

[ghost]

Will do!

[ghost]

All CLA requirements met.

[ghost]

Sorry for the delay. Should be ready for review!

[mjbvz]

Looks reasonable overall. Thanks for following up!

Can you please remove the binary file added under ./scripts though? Looks like it was committed by mistake

[ghost]

Whoops! My bad for littering. Should be fixed, thanks for the heads up!

[mjbvz]

Thanks! Will be in the next insiders build