DOC: Add crossrefs to info docstring

[athishdresu]

This PR adds the recommended cross-references to the Info docstring addressing the first batch of functions discussed in #7774

[athishdresu]

I just realized this PR accidentally included all the old commits from my previous GSoC PR. I think my local main branch wasn't updated properly before I created this new branch.The only commit actually meant for this issue is the very last one (DOC: Add crossrefs to info docstring). I am still learning the advanced parts of Git—could you let me know the best way to fix this, or if it's something you can easily filter out on your end? Sorry for the extra commits

[Aniketsy]

@athishdresu you can rebase with main and then drop the commits that are not part of this PR, in this way you can clean you PR:-- please let me know if you get stuck and need help.

[athishdresu]

@Aniketsy thanks so much for the guidance I just successfully rebased and dropped all the unrelated commits,let me know if everything looks correct now

[nordme]

Hi @athishdresu ! Thanks for the PR!

Let's put in the add_proj and del_proj functions from the Epochs class to the list here too (so far you've got Raw and Evoked proj functions).

Also, note that you'll need to change the name of your changelog rst file to doc/changes/dev/13811.other.rst since "doc" is not a valid type for changes here.

Cheers.

[athishdresu]

@nordme Thanks for the review!I've added the Epochs projection methods and updated the news fragment extension.Let me know if it looks good!