Alphabetize the shell help command

[Eliot Phillips]

If you're looking for a command and have a general idea of what it could be called, you still have to read the entire list right now to find it.

Also, if you know what command you're looking for for but don't know exactly what it's called, you still have to read the entire list.

[Juan Pablo Caram]

Fixes #158.

→ <<cset 96885c80a494>>