Also cleanup comments around redundant colons/commas in format::cleanup.

Reviewers: djasper

Subscribers: klimek, cfe-commits

Differential Revision: https://reviews.llvm.org/D24400

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@281064 91177308-0d34-0410-b5e6-96231b3b80d8