Hide day number from run chart labels
Hide day number from run chart labels

There's few enough labels being shown that these work quite well as just
months. The chart can still be moused over for individual days.


Former-commit-id: 6e2e5b98017b929fad137c2db64bf20f5b4a6f06
brandur/sorg,brandur/sorg,brandur/sorg,brandur/sorg,brandur/sorg