Fix error in string formatting

1. Fix mis-spelled key "cateegory".
2. Simplify complicated format-within-format.

Testing Done:
Manual testing.

Reviewed at https://rbcommons.com/s/twitter/r/1416/
Sync of https://github.com/pantsbuild/pants/commit/a4d6eb717296b3b3ea728093a7a01c152612beab