fix(wikidoc): sanitize generated MDX

[ss-o]

Summary

Promote the exact two-file wikidoc sanitizer change from merged next PR #94 to main.

• rewrite gomarkdoc receiver-method fragments to Docusaurus slugs
• restore escaped punctuation and entities inside paired inline-code spans
• convert generated Markdown-indented examples to fenced code blocks
• retain the regression coverage reviewed on next

Promotion integrity

• one signed commit based directly on repaired main
• only internal/wikidoc/wikidoc.go and internal/wikidoc/wikidoc_test.go change
• both promoted file blobs exactly match merged next commit f9a70b35809dca024b28d359b02a008dc506493d
• cherry-pick provenance is retained without a prohibited co-author trailer

The pre-existing red main baseline was repaired separately by #95, which closed #91 before this promotion was rebased.

Impact

The next main-branch wiki sync can update existing wiki PR #798 with working method anchors, correctly rendered inline code, and fenced brace-containing examples. This also addresses the locally reproduced Cloudflare Pages MDX failure.

Verification

• go test ./...
• go vet ./...
• GOFLAGS=-buildvcs=false go build ./...
• trunk check internal/wikidoc/wikidoc.go internal/wikidoc/wikidoc_test.go
• regenerated wiki frontmatter validation
• regenerated wiki English production build
• exact file-blob comparison against merged next

Closes #89.

Related: #85, #94, #95, z-shell/wiki#798.

[Copilot]

Pull request overview

Promotes the wikidoc sanitizer updates to ensure gomarkdoc-generated Markdown is safe and correctly rendered as Docusaurus MDX in the wiki sync pipeline (method anchors resolve, inline code renders as code, and brace-containing examples don’t break MDX parsing).

Changes:

• Convert Markdown-indented code blocks into fenced code blocks to avoid MDX interpreting braces as expressions.
• Restore gomarkdoc plain-format escaped inline-code spans by unescaping Markdown punctuation and decoding entities only within paired spans.
• Rewrite receiver-method fragment links (e.g., #Backquotes.Analyze) to the Docusaurus slugs derived from the corresponding headings.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
internal/wikidoc/wikidoc.go	Extends Sanitize with fenced-block conversion, inline-code restoration, and method-fragment slug rewriting for MDX compatibility.
internal/wikidoc/wikidoc_test.go	Adds regression tests covering method anchor rewrites, inline-code restoration, and indented-to-fenced code conversion edge cases.