Docs: Add Troubleshoot section

[molant]

Pull request checklist

Make sure you:

• Signed the Contributor License Agreement
• Followed the commit message guidelines

For non-trivial changes, please make sure you also:

• Added/Updated related documentation.

Short description of the change(s)

Fix #1464

[molant]

@ingride feel free to comment if there's anything else you think we should add!

[antross]

I don't think you meant to commit packages/extension-vscode/vscode-webhint-1.0.2.vsix. Probably should remove it (and maybe update .gitignore to exclude *.vsix so we don't add one again in the future).

Otherwise just two minor edits to the text.

[molant]

Thanks @antross, I fixed those.