coretasks: handle BOT ISUPPORT token & mode

[dgw]

Description

If the server advertises a BOT token in 005 ISUPPORT, Sopel will set that mode on itself unless that modechar appears in the value of core.modes in its configuration.

Implements part of #2079.

Checklist

• I have read CONTRIBUTING.md
• I can and do license this contribution under the EFLv2
• No issues are reported by make qa (runs make quality and make test)
• I have tested the functionality of the things this change touches
  • By the power of pytest, yes!

Notes

The default value of core.modes is B, which is the conventional modechar to advertise for BOT. Thus this won't do much on most networks unless the user overrides core.modes and doesn't know about this mode.

Support tables

Note to self: Prepped a support table update for IRCv3 here.

[Exirel]

I really like the code and the added tests. For completeness, I'd like to see 2 other test cases:

• one when core.modes contains more than one mode but none is the one in BOT
• and a second one, very similar, where core.modes contains more than one mode including the one in BOT

After all, the code does the botmodes in config and not botmodes == config.

[dgw]

@Exirel Added. @pytest.mark.parametrize is a beautiful thing… again.

[Exirel]

👼