fix(html): backtrack jsdoc summary ending with ':' to last '.'

[nanookclaw]

Closes #633.

When rendering a title-only JSDoc summary, if the trimmed plain text ends with :, walk back to the last . and shorten the rendered output to end there. If there's no ., leave the summary as-is. The fix only touches the title_only branch in create_renderer; full-markdown rendering is unchanged.

Implementation

Three private helpers added to src/html/comrak.rs:

• collect_inline_plain_text — concatenates the inline subtree's plain text (Text + Code literals; SoftBreak → space). After walk_node_title the first paragraph holds only inline nodes, so this is well-defined.
• shorten_inline_to — walks the inline tree in document order with a byte offset; shortens the literal that straddles the target and detaches later siblings.
• shorten_title_summary_trailing_colon — the policy: only act when trimmed plain text ends with : and contains a ., then target last_dot + 1. No-op otherwise.

Called between walk_node_title(root) and render_node(root.first_child(), ...).

Tests

Six unit tests in src/html/comrak.rs:

• trailing : with prior . shortens to last .
• trailing : with no . left unchanged
• no trailing : left unchanged
• trailing : after a code span backtracks past it
• trailing : after emphasis backtracks past it
• last . lives inside a code span — code span is kept up to and including ., trailing text/colon dropped

All pass via cargo test --lib html::comrak::. cargo check, cargo fmt -- --check, and deno task tailwind clean.

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[nanookclaw]

I have read the CLA Document and I hereby sign the CLA