[Documentation] Fix some invalid references in sphinx documentation

[cor3ntin]

No description provided.

[cor3ntin]

This partially fixes #68196

[github-actions]

✅ With the latest revision this PR passed the Python code formatter.

[AaronBallman]

LGTM! The only remaining issues I see when building LLVM docs locally are:

F:\source\llvm-project\llvm\docs\GitRepositoryPolicy.md:21: WARNING: 'myst' cross-reference target not found: 'DeveloperPolicy.html#adding-an-established-project-to-the-llvm-monorepo>' [myst.xref_missing]
F:\source\llvm-project\llvm\docs\InstrRefDebugInfo.md:96: WARNING: 'myst' cross-reference target not found: 'SourceLevelDebugging.html#livedebugvalues-expansion-of-variable-locations' [myst.xref_missing]
F:\source\llvm-project\llvm\docs\MarkdownQuickstartTemplate.md:161: WARNING: 'myst' cross-reference target not found: 'SphinxQuickstartTemplate.html#generating-the-documentation' [myst.xref_missing]
F:\source\llvm-project\llvm\docs\PointerAuth.md:306: WARNING: 'myst' cross-reference target not found: 'authenticated-global-relocation' [myst.xref_missing]
F:\source\llvm-project\llvm\docs\PointerAuth.md:331: WARNING: 'myst' cross-reference target not found: 'authenticated-global-relocation' [myst.xref_missing]

[xgupta]

LGTM! The only remaining issues I see when building LLVM docs locally are:

F:\source\llvm-project\llvm\docs\GitRepositoryPolicy.md:21: WARNING: 'myst' cross-reference target not found: 'DeveloperPolicy.html#adding-an-established-project-to-the-llvm-monorepo>' [myst.xref_missing]
F:\source\llvm-project\llvm\docs\InstrRefDebugInfo.md:96: WARNING: 'myst' cross-reference target not found: 'SourceLevelDebugging.html#livedebugvalues-expansion-of-variable-locations' [myst.xref_missing]
F:\source\llvm-project\llvm\docs\MarkdownQuickstartTemplate.md:161: WARNING: 'myst' cross-reference target not found: 'SphinxQuickstartTemplate.html#generating-the-documentation' [myst.xref_missing]
F:\source\llvm-project\llvm\docs\PointerAuth.md:306: WARNING: 'myst' cross-reference target not found: 'authenticated-global-relocation' [myst.xref_missing]
F:\source\llvm-project\llvm\docs\PointerAuth.md:331: WARNING: 'myst' cross-reference target not found: 'authenticated-global-relocation' [myst.xref_missing]

I saw them too, seems warnings are treated as errors by default.

[cor3ntin]

The one in PointerAuth.md are actual errors: the referenced section simply does not exist.

The two other errors are just invalid cross-document references syntaxes, I haven't looked how to fix them yet.