git-push: Accept -n as a synonym for --dry-run.

git-push is not currently using -n for anything else, and it seems
unlikely we will want to use it to mean anything else in the future,
so add it as an alias for convenience.
Signed-off-by: NNelson Elhage <nelhage@mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Documentation/git-push.txt

@@ -9,7 +9,7 @@ git-push - Update remote refs along with associated objects
 SYNOPSIS
 --------
 [verse]
-'git push' [--all | --mirror | --tags] [--dry-run] [--receive-pack=<git-receive-pack>]
+'git push' [--all | --mirror | --tags] [-n | --dry-run] [--receive-pack=<git-receive-pack>]
 	   [--repo=<repository>] [-f | --force] [-v | --verbose]
 	   [<repository> <refspec>...]
 
@@ -82,6 +82,7 @@ nor in any Push line of the corresponding remotes file---see below).
 	if the configuration option `remote.<remote>.mirror` is
 	set.
 
+-n::
 --dry-run::
 	Do everything except actually send the updates.
 

builtin-push.c

@@ -10,7 +10,7 @@
 #include "parse-options.h"
 
 static const char * const push_usage[] = {
-	"git push [--all | --mirror] [--dry-run] [--porcelain] [--tags] [--receive-pack=<git-receive-pack>] [--repo=<repository>] [-f | --force] [-v] [<repository> <refspec>...]",
+	"git push [--all | --mirror] [-n | --dry-run] [--porcelain] [--tags] [--receive-pack=<git-receive-pack>] [--repo=<repository>] [-f | --force] [-v] [<repository> <refspec>...]",
 	NULL,
 };
 
@@ -182,7 +182,7 @@ int cmd_push(int argc, const char **argv, const char *prefix)
 		OPT_BIT( 0 , "mirror", &flags, "mirror all refs",
 			    (TRANSPORT_PUSH_MIRROR|TRANSPORT_PUSH_FORCE)),
 		OPT_BOOLEAN( 0 , "tags", &tags, "push tags"),
-		OPT_BIT( 0 , "dry-run", &flags, "dry run", TRANSPORT_PUSH_DRY_RUN),
+		OPT_BIT('n' , "dry-run", &flags, "dry run", TRANSPORT_PUSH_DRY_RUN),
 		OPT_BIT( 0,  "porcelain", &flags, "machine-readable output", TRANSPORT_PUSH_PORCELAIN),
 		OPT_BIT('f', "force", &flags, "force updates", TRANSPORT_PUSH_FORCE),
 		OPT_BOOLEAN( 0 , "thin", &thin, "use thin pack"),