In the emacs mode, change gofmt errors to renumber errors or KanjiVG errors or similar

[benkasminbullock]

At the moment, if an error occurs, a message appears saying "gofmt errors", but this is confusing since it is not gofmt.

This may require copy-pasting the go Emacs mode stuff into our file. It may also be an idea to remove the dependence on the Emacs Go mode at some point.