fix: preserve math expressions in comment shortcodes (LaTeX + HTML)

[zinc75]

Problem

When a shortcode contains inline math, e.g.:

{{< question "$\hat{h}_*$" inline=true >}}

Two rendering failures occur depending on the output format.

LaTeX: pandoc.utils.stringify returns the content as a plain string with
literal dollar signs. escape_latex then escapes $ → \$ and \ →
\textbackslash{}, producing broken output in the todo:

\todo...{\$\textbackslash{}hat\{h\}\_*\$}

HTML: pandoc.Str(comment_text) inserts the text as an opaque string node.
MathJax/KaTeX never sees a pandoc.Math node and renders the dollar signs as
literal characters.

A secondary HTML issue: build_html_inline used display: inline-flex to lay
out the span contents. With a single Str node this was harmless, but once
parse_inlines splits the text into multiple nodes (Str, Math, Space…), each
node becomes a flex item and the comment renders as a column layout.

Fix

LaTeX (already in this PR): add escape_latex_with_math which splits on
$...$ regions — math is copied verbatim, surrounding text goes through
escape_latex as before.

HTML (new): add parse_inlines(text) which calls
pandoc.read(text, "markdown") and returns the inlines of the first block.
This converts $...$ into proper pandoc.Math nodes that MathJax/KaTeX
processes correctly. Use it in build_html_inline (via :extend()) and
build_html_block.

Also replace display: inline-flex / align-items / gap with
display: inline-block / vertical-align: baseline in build_html_inline to
prevent the column-layout artifact.

Result

{{< question "Define $\hat{h}_*$ and $\hat{h}$." inline=true >}}

LaTeX: renders correctly as:

\todo...{Define $\hat{h}_*$ and $\hat{h}$.}

HTML: math is rendered by MathJax/KaTeX; inline comment box has correct
rectangular border with no column artifacts.

[zinc75]

@vgreg : Gently reminder : did you have time to look at my pull request ? This allows the use of maths in comments which is useful for many use cases 🙂

[vgreg]

@vgreg : Gently reminder : did you have time to look at my pull request ? This allows the use of maths in comments which is useful for many use cases 🙂

Thank you for this contribution.
Can you make the fix in my comment above? It looks all good otherwise.

[zinc75]

@vgreg : Gently reminder : did you have time to look at my pull request ? This allows the use of maths in comments which is useful for many use cases 🙂

Thank you for this contribution. Can you make the fix in my comment above? It looks all good otherwise.

Fix done in f368b83 💯