The parse-options machinery learned to refrain from enclosing
placeholder string inside a "<bra" and "ket>" pair automatically
without PARSE_OPT_LITERAL_ARGHELP.  Existing help text for option
arguments that are not formatted correctly have been identified and
fixed.

* rs/parse-opt-lithelp:
  parse-options: automatically infer PARSE_OPT_LITERAL_ARGHELP
  shortlog: correct option help for -w
  send-pack: specify --force-with-lease argument help explicitly
  pack-objects: specify --index-version argument help explicitly
  difftool: remove angular brackets from argument help
  add, update-index: fix --chmod argument help
  push: use PARSE_OPT_LITERAL_ARGHELP instead of unbalanced brackets