Markdown guides: language syntax highlighting not in place

[SueChaplain]

Describe the bug

Adding syntax highlighting for xml files in markdown source does not render any colour in the built HTML.

For example:

<!-- OpenLiberty runtime -->
<liberty.groupId>io.openliberty</liberty.groupId>
<liberty.artifactId>openliberty-runtime</liberty.artifactId>
<version.openliberty-runtime>19.0.0.8</version.openliberty-runtime>
<http.port>9080</http.port>
<https.port>9443</https.port>
<packaging.type>usr</packaging.type>
<app.name>${project.artifactId}</app.name>
<package.file>${project.build.directory}/${app.name}.zip</package.file>

Text is just orange and not a combination of green and orange as generated when built from AsciiDoc. The HTML source is marked up, so possibly a CSS issue.

<div class="language-xml highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="c">&lt;!-- OpenLiberty runtime --&gt;</span>
  | <span class="nt">&lt;liberty.groupId&gt;</span>io.openliberty<span class="nt">&lt;/liberty.groupId&gt;</span>

Expected behavior

Code highlighted in green and orange

Actual behavior

Code only highlighted in orange

Steps to reproduce the bug

Add the example above into a markdown guide and build locally.

Environment where the bug occurred

• Firefox (Desktop)
• Safari (Desktop)
• Chrome (Desktop)
• Internet Explorer (Desktop)
• iOS (Mobile)
• Android (Mobile)

Screenshots

If applicable, add screenshots to help explain your problem.

Additional context

[alohr51]

@SueChaplain currently with our setup that is a limitation with markdown guides. the syntax highlighting is only a feature for asciidoc currently.

[alohr51]

Someone can take a look into https://github.com/kramdown/syntax-coderay (although I would suggest against it since it doesn't look highly maintained) but again, this is already available using asciidoc guides

[SueChaplain]

I was assuming this would be supported by the build: https://www.markdownguide.org/extended-syntax/#syntax-highlighting

Is that not possible?

[alohr51]

Our setup uses Kramdown which needs a 3rd party gem (the link I added above) to be installed to support syntax highlighting. It seems poorly maintained so it could be risky to add it as a dependency.

[SueChaplain]

Looks like Rouge is the default these days: https://kramdown.gettalong.org/syntax_highlighter/rouge.html