(Feature request) Syntax highlight for code blocks

[eliandoran]

Describe feature

This goes without saying, it's one of the most requested features from the people I've known using Trilium for taking notes related to software development.

Additional Information

Some notes I've took in the past:

Apparently the syntax highlighting is not supported in the CKEditor, which is the reason that code blocks within text notes do not have syntax highlight.

• Syntax highlighting on code blocks? #1803

Some works has already been done to try to integrate some kind of syntax highlight in CKEditor:

• Added syntax highlighting to code-blocks (and it works!) #2198
  • Huge amount of changes (-11k deletions).
  • Only a proof of concept, not meant to be merged.
• [Widget] Syntax Highlight Widget #2822
  • This is actually a fully-fledged implementation which uses highlight.js.
  • Works as a custom script.
  • Seems quite good, actually, although its README is out of date.

[liuxiawei]

Thanks to these efforts, can we realize the display of line numbers?