fix(prism): apply syntax highlighting to dynamically created code elements

[developerfred]

Summary

Fixes #8 - Prism.js styles not applying on form submit.

When users change secondary languages and click Compare, the syntax highlighting styles were not applied until page reload.

Changes

• Changed code element classes from custom-${lang} to language-${lang} to match Prism.js expected pattern
• Added Prism.highlightAllUnder(section) in createLiSection() to apply highlighting to dynamically created elements
• Optimized to apply highlighting only to specific sections instead of re-highlighting the entire page

Technical Details

The fix addresses two issues:

1. Prism.js only recognizes classes matching the pattern language-xxxx, not custom-xxxx
2. Prism.highlightAll() was not being called after dynamic element creation

By using Prism.highlightAllUnder(section) within createLiSection(), highlighting is applied efficiently to newly created elements only, improving performance.

Closes #8

[Kernix13]

I deliberately changed language- to custom- because the list items looked horrible that way. I'm using the list items as quick syntax compares and I do not need a black background for the inline code element.

I'm also seeing This branch has conflicts that must be resolved in the PR. I had no idea you created a PR - I changed changed my file structure so index.js is now in the js folder.

[Kernix13]

I forgot about this issue and the fact that the pre code blocks were not showing syntax highlighting.

[Kernix13]

I apologize for just noticing your PRs today. I was not getting notifications for this repo - I just changed that. Let me know how you would like to handle your 2 PRs because I do not want to change custom- to language- for the li items, and index.js has been moved.

[developerfred]

@Kernix13 Thank you for the feedback, I will adapt my pull requests to include your update.