Create ROT13 Command

[bradleysigma]

Create ROT 13 command. Semi-imported from the Slack !caesar command. Can be used as an alternative to ||spoilers||, with the distinction that the general shape of the message can be seen e.g. below the first use is identifiable as enciphering a URL. Has a context menu option, which responds with an ephemeral message; only shows the (probable) decryption to the user that called it, instead of publishing to the entire channel. Discord bots are limited to five context menu listings (for some reason), so either the context menu version of Zalgo or Mock (or both) would have to be removed for this to be added; both are currently commented out, but could uncomment one if there is a consensus. This has a meaningful usecase for the context menu version (to privately decrypt a version encrypted with the slash version), which Zalgo is kinda lacking.

[bradleysigma]

Another difference it has to ||spoiler|| is that for this, you have the option to use an external tool to decode the message word by word, if you wish to attempt to see where a message is going and possibly cut yourself off part way though, instead of only having the option to reveal the entire message as a whole.

[andrewj-brown]

LGTM, pending discussion on context menu.

I'll add it to our infra to-do-list; we're currently at the limit of 5 commands (3 from text.py, plus the mod-only starboard blacklist/whitelist commands).

[bradleysigma]

I'll add it to our infra to-do-list

What's longer, the Infra to-do list, or @LimaoC's Outgoing Secretary to-do list?

[LimaoC]

@LimaoC's Outgoing Secretary to-do list

No such list exists, this is a fabricated lie made up by @bradleysigma

[bradleysigma]

But here you give confirmation of the list's existence; were you lying then or are you lying now?

[andrewj-brown]

I'll add it to our infra to-do-list

What's longer, the Infra to-do list, or @LimaoC's Outgoing Secretary to-do list?

Presumably the infra list, which is currently at 23 items (plus sub-items).

Our plan is to hold a meeting sometime within a month, so hopefully this PR doesn't have to wait too long. I've converted to draft as an interim measure.