Merge branch 'mg/placeholders-are-lowercase' into maint

* mg/placeholders-are-lowercase:
Make <identifier> lowercase in Documentation
Make <identifier> lowercase as per CodingGuidelines
Make <identifier> lowercase as per CodingGuidelines
Make <identifier> lowercase as per CodingGuidelines
CodingGuidelines: downcase placeholders in usage messages

diff --cc builtin/merge.c
Simple merge