Line numbers can be converted to emoji

[mwchase]

Encountered in version 1.2.1.

Let me see if this pastes cleanly.

src/motr/controllers/base.py:117: error: working_memory of _default is 30 
exceeding threshold of 20
src/motr/_api/package.py💯 error: working_memory of package_under_test is 24 
exceeding threshold of 20
src/motr/_api/package.py:107: error: working_memory of put is 24 exceeding 
threshold of 20

That's not GitHub turning :100: into 💯. That's just actually what came back on the command line.