Broken parameter documentation with raw identifiers

[a7medev]

Description

Retrieving a structured documentation comment for a function with a parameter whose name uses raw identifiers that contains a colon : doesn't work.

Reproduction

This could be easily reproduced using by triggering the SourceKit's Cursor Info against function foo or bar.

/// - Parameters:
///   - `a: b`: The first parameter.
func foo(`a: b`: Int) {}

/// - Parameter `a: b`: The first parameter.
func bar(`a: b`: Int) {}

The (formatted) output XML documentation for function foo is:

<Function file="<...>/File.swift" line="3" column="6">
  <Name>foo(a: b:)</Name>
  <USR>s:4File3foo0015ab_BcaJIIBtnfaeySi_tF</USR>
  <Declaration>func foo(`a: b`: Int)</Declaration>
  <CommentParts></CommentParts>
</Function>

Notice that CommentParts is empty.

The same behavior occurs if we omit the backticks surrounding the parameter name in the doc comment as follows:

/// - Parameters:
///   - a: b: The first parameter.
func foo(`a: b`: Int) {}

/// - Parameter a: b: The first parameter.
func bar(`a: b`: Int) {}

as the parameter name gets parsed as the thing before the first : which would be just a instead of a: b for both foo and bar.

Expected behavior

Parameter documentation is parsed and returned correctly for parameters names that use raw identifiers and contain a colon :.

Environment

Apple Swift version 6.2-dev (LLVM 0bd84aacb66971d, Swift 0839675)
Target: arm64-apple-macosx15.0
Build config: +assertions

Additional information

No response

[a7medev]

I think this could be a good first issue.