add !!help command

[gooh]

Add a command that will list all commands Jeeves is currently capable of handling, e.g.

Gordon: !!help
Jeeves: Supported commands: `about`, `docs`, `man`, `swordfighting`. Type `!!help command` to learn more about an individual command.
Gordon: !!help man
Jeeves: Lists the man page for a shell command. Usage: `!!man shellcommand`

[krakjoe]

PING REALLY VERY EXTREMELY HARD @DaveRandom @PeeHaa

Go ...

[PeeHaa]

The list of supported commands (including the status enable/disabled and possible aliases) is support by !!plugin list:

plugin [list|disable|enable] [plugin-name]

[DaveRandom]

The only reason this isn't a thing already is that I couldn't be bothered writing the actual help text. I will document the built-in commands soon though.

[DaveRandom]

Built-in commands are !!admin, !!command, !!plugin, !!ban/!!unban and !!version.