Fix svelte special chars escaping problem

[mishig25]

Problem description

< & { are special characters in svelte syntax. Therefore, you can't write a doc content like 4<5. To fix this problem, we were escaping those characters with their respective html codes (lt; & lcub;) in our python code using regexes. These regexs were slow, which was fixed in #373 and #394. However, there were still some errors

Solution

Fix it at markdown/mdsvex AST level using a custom remark plugin
AST Playground

Description of the custom remark plugin

When AST tree is being traversed, if a node type is "text" (rather than "html"), then escape < & { with < & {. This solution works great! The only catch is that we lost the full capability of svelte syntax. {4+5} will be evaluated as string {4+5} rather than js compute statement of 9. I think it is fine since we dont't have any inline js compute statements in the docs mdx files. Usage of custom components (such as <Tip>, <Question>) should still work as expected

As a side effect, this PR should also decrease the build time since we are removing a lot regex checks in python and using already done AST tree traversal in mdsvex

todo:

• katex issue should be fixed in this PR as well (fixed in fd61ec1)

[Wauplin]

Really nice, thanks @mishig25 ! 🚀

[coyotte508]

Thanks, will help a lot for huggingface.js too iirc