Merge branch 'bc/sign-commit-with-custom-encoding'

Merge branch 'bc/sign-commit-with-custom-encoding'

Signing commit with custom encoding was passing the data to be
signed at a wrong stage in the pipeline, which has been corrected.

* bc/sign-commit-with-custom-encoding:
  commit: sign commit after mutating buffer
  commit: name UTF-8 function appropriately