Merge #6320 #6321

6320: Textmate grammar: prevent line comments from breaking block comments (closes #6281) r=matklad a=dustypomerleau

Fixes https://github.com/rust-analyzer/rust-analyzer/issues/6281.

Previously, line comments were able to break block comments by essentially commenting out the closing `*/`, resulting in a never-ending comment. This PR splits block comments into a separate repository group to fix this problem.

Since the comment scopes also include ignored parameters and inferred types, I've added the change proposed by @bnjjj in https://github.com/rust-analyzer/rust-analyzer/pull/6317, in order to close https://github.com/rust-analyzer/rust-analyzer/issues/6311 as well.

6321: Fix opening module documentation opening parent documentation instead r=matklad a=zacps

The whole path/URL joining code is kind of ugly which is what led to
this, but at the same time I don't really want to rewrite it right
now...

Fixes https://github.com/rust-analyzer/rust-analyzer/issues/6286

Co-authored-by: Dusty Pomerleau <[email protected]>
Co-authored-by: Zac Pullar-Strecker <[email protected]>