Introduce the "subcommand" mode to parse-options API and update the
command line parser of Git commands with subcommands.
* sg/parse-options-subcommand: (23 commits)
remote: run "remote rm" argv through parse_options()
maintenance: add parse-options boilerplate for subcommands
pass subcommand "prefix" arguments to parse_options()
builtin/worktree.c: let parse-options parse subcommands
builtin/stash.c: let parse-options parse subcommands
builtin/sparse-checkout.c: let parse-options parse subcommands
builtin/remote.c: let parse-options parse subcommands
builtin/reflog.c: let parse-options parse subcommands
builtin/notes.c: let parse-options parse subcommands
builtin/multi-pack-index.c: let parse-options parse subcommands
builtin/hook.c: let parse-options parse subcommands
builtin/gc.c: let parse-options parse 'git maintenance's subcommands
builtin/commit-graph.c: let parse-options parse subcommands
builtin/bundle.c: let parse-options parse subcommands
parse-options: add support for parsing subcommands
parse-options: drop leading space from '--git-completion-helper' output
parse-options: clarify the limitations of PARSE_OPT_NODASH
parse-options: PARSE_OPT_KEEP_UNKNOWN only applies to --options
api-parse-options.txt: fix description of OPT_CMDMODE
t0040-parse-options: test parse_options() with various 'parse_opt_flags'
...