Merge branch 'pb/complete-diff-options'

Completion updates.

* pb/complete-diff-options: (24 commits)
  diff.c: mention completion above add_diff_options
  completion: complete --remerge-diff
  completion: complete --diff-merges, its options and --no-diff-merges
  completion: move --pickaxe-{all,regex} to __git_diff_common_options
  completion: complete --ws-error-highlight
  completion: complete --unified
  completion: complete --output-indicator-{context,new,old}
  completion: complete --output
  completion: complete --no-stat
  completion: complete --no-relative
  completion: complete --line-prefix
  completion: complete --ita-invisible-in-index and --ita-visible-in-index
  completion: complete --irreversible-delete
  completion: complete --ignore-matching-lines
  completion: complete --function-context
  completion: complete --find-renames
  completion: complete --find-object
  completion: complete --find-copies
  completion: complete --default-prefix
  completion: complete --compact-summary
  ...

diff.c

@@ -5520,6 +5520,10 @@ static int diff_opt_rotate_to(const struct option *opt, const char *arg, int uns
 	return 0;
 }
 
+/*
+ * Consider adding new flags to __git_diff_common_options
+ * in contrib/completion/git-completion.bash
+ */
 struct option *add_diff_options(const struct option *opts,
 				struct diff_options *options)
 {