docs: update and improve rocq documentation

[Durbatuluk1701]

This PR updates the Rocq documentation. In particular, the following changes are made:

• Various rocq{dep, top, etc.} -> rocq {dep, top, etc.} updates (the separate Rocq binaries to Rocq subcommand changes)
• Changes to the (stdlib {yes,no}) descriptions and clarified the Corelib vs. Stdlib behaviors
• Other minor spacing/grammatical changes

[rlepigre-skylabs-ai]

The changes look good to me.

[Durbatuluk1701]

One thing I'd thought of while doing these updates: is (stdlib ...) poorly named now? I know sometimes I am even confused because it seems like it should be including the Stdlib when in reality it is just Corelib.

Would changing its name to something like (prelude ...) or (corelib ...) make more sense?
cc. @Alizter @rlepigre-skylabs-ai

[Alizter]

@Durbatuluk1701 Could you create an issue about it? I am not sure how Rocq works with respect to the standard library / core library now. I don't know if such a field is still needed so it would be good to review the overall design.

[rlepigre-skylabs-ai]

This is still needed, but the only use-case is building Corelib itself. That is, when enabling the default dune rules in the Rocq repository as part of a composed build for example (by default Rocq uses custom rules). Perhaps the option should be set via something like (no_corelib) instead of a yes/no flag.