FR: Anchor validation warning should remind the user it's case sensitive, especially if there are case-insensitive matches.

[ilyagr]

With MkDocs 1.6 and validation: anchors: warn, I had this warning:

WARNING -  Doc file 'github.md' contains a link 'tutorial.md#Conflicts', but the doc 'tutorial.md' does not contain an anchor '#Conflicts'.

while tutorial.md did contain a subheading:

...

## Conflicts

...

Changing the anchor in tutorial.md from tutorial.md#Conflicts to tutorial.md#conflicts fixed the issue. However, I think MkDocs should have compared the anchors case-insensitively form the beginning. the warning was confusing.

Cc the similar #3690, but this bug has a smaller scope and has nothing to do with extensions.

Thank you very much for adding this feature!

[ilyagr]

Alternatively, if case sensitivity is expected, please consider changing the warning to emphasize that it's case-sensitive, at least if there is a heading that matches case-insensitively. I was confused for quite a bit.

[pawamoy]

My browser seems to be case sensitive too though (Firefox), so the warning would be valid in my case.

[ilyagr]

Good point! VS Code was not case sensitive, so I didn't realize.

I'll change the title to make this into a feature request to adjust the warning.