Merge branch 'jc/mailmap-case-insensitivity'

The mailmap mechanism unnecessarily downcased the e-mail addresses in the output, and also ignored the human name when it is a single character name. This now has become Eric Sunshine's series, even though it still is under jc/ hierarchy. * jc/mailmap-case-insensitivity: mailmap: style fixes mailmap: debug: avoid passing NULL to fprintf() '%s' conversion specification mailmap: debug: eliminate -Wformat field precision type warning mailmap: debug: fix malformed fprintf() format conversion specification mailmap: debug: fix out-of-order fprintf() arguments mailmap: do not downcase mailmap entries t4203: demonstrate loss of uppercase characters in canonical email mailmap: do not lose single-letter names t4203: demonstrate loss of single-character name in mailmap entry