Bugfix: brew_update_formula.py
Bugfix: brew_update_formula.py

Sample command output is:

    Error: This command updates brew itself, and does not take formula names.
    Use 'brew upgrade thefuck' instead.

This will never match the previous `"Use 'brew upgrade <formula>'" in command.output` test.
nvbn/thefuck,Clpsplug/thefuck,scorphus/thefuck,Clpsplug/thefuck,SimenB/thefuck,scorphus/thefuck,SimenB/thefuck,nvbn/thefuck