submodule documentation: add options to the subcommand

When reading up on a subcommand of `git submodule <subcommand>`,
it is convenient to have its options nearby and not just at the
top of the man page.  Add the options to each subcommand.

While at it, also document the `--checkout` option for `update`.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: stefanbeller

Documentation/git-submodule.txt

@@ -9,17 +9,12 @@ git-submodule - Initialize, update or inspect submodules
 SYNOPSIS
 --------
 [verse]
-'git submodule' [--quiet] add [-b <branch>] [-f|--force] [--name <name>]
-	      [--reference <repository>] [--depth <depth>] [--] <repository> [<path>]
+'git submodule' [--quiet] add [<options>] [--] <repository> [<path>]
 'git submodule' [--quiet] status [--cached] [--recursive] [--] [<path>...]
 'git submodule' [--quiet] init [--] [<path>...]
 'git submodule' [--quiet] deinit [-f|--force] (--all|[--] <path>...)
-'git submodule' [--quiet] update [--init] [--remote] [-N|--no-fetch]
-	      [--[no-]recommend-shallow] [-f|--force] [--rebase|--merge]
-	      [--reference <repository>] [--depth <depth>] [--recursive]
-	      [--jobs <n>] [--] [<path>...]
-'git submodule' [--quiet] summary [--cached|--files] [(-n|--summary-limit) <n>]
-	      [commit] [--] [<path>...]
+'git submodule' [--quiet] update [<options>] [--] [<path>...]
+'git submodule' [--quiet] summary [<options>] [--] [<path>...]
 'git submodule' [--quiet] foreach [--recursive] <command>
 'git submodule' [--quiet] sync [--recursive] [--] [<path>...]
 'git submodule' [--quiet] absorbgitdirs [--] [<path>...]
@@ -63,7 +58,7 @@ if you choose to go that route.
 
 COMMANDS
 --------
-add::
+add [-b <branch>] [-f|--force] [--name <name>] [--reference <repository>] [--depth <depth>] [--] <repository> [<path>]::
 	Add the given repository as a submodule at the given path
 	to the changeset to be committed next to the current
 	project: the current project is termed the "superproject".
@@ -104,7 +99,7 @@ together in the same relative location, and only the
 superproject's URL needs to be provided: git-submodule will correctly
 locate the submodule using the relative URL in .gitmodules.
 
-status::
+status [--cached] [--recursive] [--] [<path>...]::
 	Show the status of the submodules. This will print the SHA-1 of the
 	currently checked out commit for each submodule, along with the
 	submodule path and the output of 'git describe' for the
@@ -121,7 +116,7 @@ submodules with respect to the commit recorded in the index or the HEAD,
 linkgit:git-status[1] and linkgit:git-diff[1] will provide that information
 too (and can also report changes to a submodule's work tree).
 
-init::
+init [--] [<path>...]::
 	Initialize the submodules recorded in the index (which were
 	added and committed elsewhere) by copying submodule
 	names and urls from .gitmodules to .git/config.
@@ -136,7 +131,7 @@ init::
 	the explicit 'init' step if you do not intend to customize
 	any submodule locations.
 
-deinit::
+deinit [-f|--force] (--all|[--] <path>...)::
 	Unregister the given submodules, i.e. remove the whole
 	`submodule.$name` section from .git/config together with their work
 	tree. Further calls to `git submodule update`, `git submodule foreach`
@@ -152,7 +147,7 @@ instead of deinit-ing everything, to prevent mistakes.
 If `--force` is specified, the submodule's working tree will
 be removed even if it contains local modifications.
 
-update::
+update [--init] [--remote] [-N|--no-fetch] [--[no-]recommend-shallow] [-f|--force] [--checkout|--rebase|--merge] [--reference <repository>] [--depth <depth>] [--recursive] [--jobs <n>] [--] [<path>...]::
 +
 --
 Update the registered submodules to match what the superproject
@@ -198,7 +193,7 @@ submodule with the `--init` option.
 If `--recursive` is specified, this command will recurse into the
 registered submodules, and update any nested submodules within.
 --
-summary::
+summary [--cached|--files] [(-n|--summary-limit) <n>] [commit] [--] [<path>...]::
 	Show commit summary between the given commit (defaults to HEAD) and
 	working tree/index. For a submodule in question, a series of commits
 	in the submodule between the given super project commit and the
@@ -211,7 +206,7 @@ summary::
 Using the `--submodule=log` option with linkgit:git-diff[1] will provide that
 information too.
 
-foreach::
+foreach [--recursive] <command>::
 	Evaluates an arbitrary shell command in each checked out submodule.
 	The command has access to the variables $name, $path, $sha1 and
 	$toplevel:
@@ -232,7 +227,7 @@ As an example, +git submodule foreach \'echo $path {backtick}git
 rev-parse HEAD{backtick}'+ will show the path and currently checked out
 commit for each submodule.
 
-sync::
+sync [--recursive] [--] [<path>...]::
 	Synchronizes submodules' remote URL configuration setting
 	to the value specified in .gitmodules. It will only affect those
 	submodules which already have a URL entry in .git/config (that is the