Add: markdown code block langs

[mattmundell]

What:

Add languages to ``` blocks in Markdown files in the Rust tree. Also remove no_run from these files.

Why:

Enables syntax highlighting.

From what I can see no_run is only for comments in Rust code.

[Tehforsch]

Hi, thank you.

From what I can see no_run is only for comments in Rust code.

This is true, but some of these markdown files are included from within the rust code as docstrings for their corresponding modules via #![doc = include_str!("README.md")], so unfortunately we cannot return the no_run directives.

[mattmundell]

Oh I see, I'll make a new PR.

Would it be a good idea to add no_run to all the rust blocks?

[Tehforsch]

Would it be a good idea to add no_run to all the rust blocks?

I don't think so, since we want those code blocks to run as doctests. Simply leaving the no_run as it is should be fine. It is a bit unfortunate that this shows up in the readmes and looks ugly, but as far as I know, fixing this requires some additional tooling such as https://github.com/orium/cargo-rdme , which is a little overkill for our purposes.