Use colour to help with legibility in error message for `--sniffs` and `--exclude` parameters

[fredden]

While working on #344, some additional improvements were raised. In order to not forget about the suggestion, this issue has been opened.

It would help with legibility of the error messages if we were to add some colour to the output. Of course, this should only happen if coloured output has been requested via the --colors parameter. For an example, notice the difference between phpcs --help and phpcs --colors --help.

[jrfnl]

Loosely related to #448