maintenance: fix synopsis in documentation

The synopsis for 'git maintenance' did not include the commands other
than the 'run' command. Update this to include the others. The 'start'
command is the only one of these that parses additional options, and
then only the --scheduler option.

Also move the 'register' command down after 'stop' and before
'unregister' for a logical grouping of the commands instead of an
alphabetical one. The diff makes it look as three other commands are
moved up.

Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-maintenance.txt

@@ -10,6 +10,8 @@ SYNOPSIS
 --------
 [verse]
 'git maintenance' run [<options>]
+'git maintenance' start [--scheduler=<scheduler>]
+'git maintenance' (stop|register|unregister)
 
 
 DESCRIPTION
@@ -29,6 +31,24 @@ Git repository.
 SUBCOMMANDS
 -----------
 
+run::
+	Run one or more maintenance tasks. If one or more `--task` options
+	are specified, then those tasks are run in that order. Otherwise,
+	the tasks are determined by which `maintenance.<task>.enabled`
+	config options are true. By default, only `maintenance.gc.enabled`
+	is true.
+
+start::
+	Start running maintenance on the current repository. This performs
+	the same config updates as the `register` subcommand, then updates
+	the background scheduler to run `git maintenance run --scheduled`
+	on an hourly basis.
+
+stop::
+	Halt the background maintenance schedule. The current repository
+	is not removed from the list of maintained repositories, in case
+	the background maintenance is restarted later.
+
 register::
 	Initialize Git config values so any scheduled maintenance will
 	start running on this repository. This adds the repository to the
@@ -55,24 +75,6 @@ task:
 setting `maintenance.auto = false` in the current repository. This config
 setting will remain after a `git maintenance unregister` command.
 
-run::
-	Run one or more maintenance tasks. If one or more `--task` options
-	are specified, then those tasks are run in that order. Otherwise,
-	the tasks are determined by which `maintenance.<task>.enabled`
-	config options are true. By default, only `maintenance.gc.enabled`
-	is true.
-
-start::
-	Start running maintenance on the current repository. This performs
-	the same config updates as the `register` subcommand, then updates
-	the background scheduler to run `git maintenance run --scheduled`
-	on an hourly basis.
-
-stop::
-	Halt the background maintenance schedule. The current repository
-	is not removed from the list of maintained repositories, in case
-	the background maintenance is restarted later.
-
 unregister::
 	Remove the current repository from background maintenance. This
 	only removes the repository from the configured list. It does not