Clarify if sessions are resumable for each gateway close code

[Zoddo]

This PR (which was made after this DDevs thread) attempts to clarify which gateway close codes are potentially resumable, and which ones are not worth trying to resume.

The idea is that libs can immediately reset the shard's session state upon encountering a non-resumable close code, saving a useless connection to the gateway_resume_url.

The information on whether a close code is resumable or not is based solely on my own testing (except for 4001, which has been confirmed to never be resumable by @mrkirby153 in the aforementioned thread).

[Zoddo]

I'm not sure why the CI fails on the table formatting, everything is correctly aligned when pasting it in an editor with a fixed-width font.

[valdotle]

I'm not sure why the CI fails on the table formatting, everything is correctly aligned when pasting it in an editor with a fixed-width font.

I think you have a double space at the end of the second row from the right

[mrkirby153]

I think it makes more sense to have the table split into two columns: reconnect and resume.

So it'd look something like

Close Code	Reconnect	Resume
1234	true	false
5678	false	false

[Zoddo]

Yeah, I hesitated, but a single Action column looked more readable.

I'm updating the PR to use 2 columns.

[Zoddo]

Rebased changes on main