[SR-14026] Doc comment for closure parameters of function parameter: work for top level func, but not nested member func

[mattyoung]

Previous ID	SR-14026
Radar	rdar://problem/73014684
Original Reporter	@mattyoung
Type	New Feature

Attachment: Download

Additional Detail from JIRA

Votes	0
Component/s	SourceKit-LSP
Labels	New Feature
Assignee	None
Priority	Medium

md5: ca46ad50f3aae96616db4981525f6201

Issue Description:

For nested in either an extension or struct member func, the closure parameter doc comment on quick help (option click on symbol in Xcode) show correctly at definition, but not at call site: show "No description"

See: https://forums.swift.org/t/doc-comment-how-to-document-closure-arguments-of-func-argument/41940/9

ClosureParamDocCommentBug.swift

[typesanitizer]

@swift-ci create

[benlangmuir]

Another difference is that when you click on the declaration the type is shown with the full `(_ first: Element, _ second: Element)` syntax, but when you click on the call it is collapsed to `(Element, Element)`. We should also check the behaviour across module boundaries.