Merge branch 'rs/c-auto-resets-attributes' into maint

When "%C(auto)" appears at the very beginning of the pretty format
string, it did not need to issue the reset sequence, but it did.
This is a small optimization to already graduated topic.

* rs/c-auto-resets-attributes:
  pretty: avoid adding reset for %C(auto) if output is empty
  pretty: let %C(auto) reset all attributes

diff --cc pretty.c
Simple merge