Fix types of @next/mdx (#82238)
### What?
This fixes a couple of things:
- Although it’s rare for MDX plugins to accept more than 1 option, they
may accept any number of arguments.
- In addition to `remarkPlugins` and `rehypePlugins`, now `recmaPlugins`
is also patched to accept strings
- TypeScript property Descriptions are preserved for patched values.
### Why?
Because it is broken.
### How?
Fixes #77297
