_git: fix git add -u/-A/...
_git: fix git grep -A/-B/-C
_git: fix --column
_git: fix fast-import --cat-blob-fd
_git: fix count-objects -H

-H can be used with other options
_git: rev-parse --resolve-git-dir: only complete directories
_git: fix send-email --smtp-debug
_git: make --abbrev-commit and --no-abbrev-commit mutually exclusive
_git: --min-parents and --max-parents dont exclude each other, also force a numeric argument
_git: fix --recurse-submodules / --recurse-submodules-default / --submodule-prefix
_git: add 'submodule deinit' command
_git: add new configuration options
_git: fix wrong default value
_git: fix casing of config option
_git: fix some typos