Add cape, lspce, and eldoc-box

[cyrialize]

This PR adds the following packages:

• cape - a package by the creator of corfu, it provides completion at point extensions. I added this package as a sub-bullet to cape.
• lspce - another LSP implementation - I've yet to try this one, but I have found interesting notes on it on reddit
• eldoc-box - childframes for eldoc - I added this as a sub-bullet to eldoc

[cyrialize]

I made a separate pr to resolve the links flagged by check_links_with_awesome_bot: #509

[cyrialize]

@jcs090218 Hello! Would you be able to re-run the check_links_with_awesome_bot action? I don't think I have the ability to do that.

I saw in the errors that it was due to the Emacs wiki being unavailable. It does seem like it's available now, so the action could probably be re-run.

[jcs090218]

LGTM! Thank you! :D