Add syntax highlighting to Clojure documentation codeblocks

[isaiasvallejos]

Add syntax highlighting to codeblocks from Clojure documentation when viewed in IntelliJ's documentation window, improving readability and comprehension within the docs code.

Solves issue: https://github.com/clojure-lsp/clojure-lsp-intellij/issues/38

Key changes:

• Upgraded markdown-clj to version 1.12.1, which introduces the :codeblock-callback argument that enables the integration of a callback function to parse codeblocks from the documentation markdown, facilitating the addition of a highlight function
  • markdown-clj documentation regarding codeblock callbacks
• Implemented the use of SyntaxHighlighter and Lexer to traverse through code tokens extracted from the codeblocks. Additionally, utilized EditorColorsScheme to obtain font color, background color, and font style attributes (bold and italic).
  • The code walking process is managed through .start and .advance methods from lexer, handling each code token such as parentheses ( ), defn, variable names, etc.
• Based on the extracted token attributes, encapsulate each token within an HTML <span> element, applying inline styles to mimic the desired syntax highlighting effect translating the token attributes to CSS.

How to test:

Run plugin, install a theme or use a default one and try out.

Preview:

Using theme "One Dark Vivid Italic", before/after:

[isaiasvallejos]

@ericdallo Suggestions applied! Thanks a lot.

Also added the CHANGELOG in the unreleased section, that's correct? Let me know if we need anything else.

PS: I didn't rebase the commits, so on merge, maybe we need to do a squash.

[ericdallo]

It looks and works great! Thank you for your first contribution!