`define` command should match punctuation and spacing variants

[Matt Cloyd]

Expected:
@Charlie define returns the definition for "back end developer" when any of the following searches are run:

@Charlie define back end developer
@Charlie define back-end developer
@Charlie define backend developer

Actual:
Only the exact search (back end developer) matches.

This will be an issue with many terms, e.g. A-11 vs A11. The goal of this issue is making it so folks don't have to guess at spacing and punctuation.