feat: highlight code blocks

[timonv]

Hey there, love the simplicity of tui-markdown. Using this for a project that renders code, and I noticed it was adding an extra new line after starting the codeblock, and adding newlines between each code line. Additionaly, the code event does not get triggered.

After fixing that, I figured code highlighting would be cool. Added it behind a feature flag as the library is not lightweight.

Added tests with insta. Since the github pipeline is not in the same repository, I couldn't test for both features. Perhaps using cargo-hack with --each-feature is a nice solution.

Might be nice to also set a background for the full block, with the maximum line length from the full block. Current solution and syntect just do line length, which in my opinion doesn't look great.

[timonv]

Hmm I think Code is actually used for inline snippetes

[timonv]

Fixed 👌

[joshka]

Generally LGTM. I started to review this earlier this week, but didn't hit submit. Apologies on the delay. A few minor comments.

[joshka]

I wonder if there's a good way to write this as a multi-line string instead of with inline \n characters?

[timonv]

Is it always the expression inside the macro? Maybe it's an idea to assign variables with descriptive names.

[timonv]

Seems to work by assigning to a variable first, I've also changed the blocks slightly so it's a bit easier when reviewing

[joshka]

In theory this could also be manually written in yaml as something like

expression: |
    from_str(indoc!{"
    ...

From some naive testing, insta doesn't seem to care too much about the expression regardless, so the indoc parts are probably unnecessary there either (their effect is just to remove the initial indentation in the rust code). This is not a big deal however.

[timonv]

Thanks for the feedback! Updated the PR.

[timonv]

Hmm after 09353f1 some indentation is missing

Added a test to verify, looks alright

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 97.22222% with 1 line in your changes missing coverage. Please review.

Project coverage is 41.68%. Comparing base (65241aa) to head (168da5e).

Files with missing lines	Patch %	Lines
tui-markdown/src/lib.rs	97.22%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #51      +/-   ##
==========================================
+ Coverage   37.66%   41.68%   +4.01%     
==========================================
  Files           5        5              
  Lines         446      475      +29     
==========================================
+ Hits          168      198      +30     
+ Misses        278      277       -1     

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[joshka]

The ratatui/underline-color feature was added automatically due to feature unification at the workspace level (due to markdown-reader pulling in ratatui/default). This is probably a small problem for targets that don't have this feature available, but if it's one that causes problems, this can be solved in another PR I think.

[joshka]

I enabled this by default. To disable set default-features = false.

[joshka]

Thanks for the PR @timonv