[PATCH] fix cat-file usage message and documentation

cat-file with an object on the command line requires an
option to tell it what to output (type, size, pretty-print,
etc). However, the square brackets in the usage imply that
those options are not required. This patch switches them to
parentheses to indicate "required but grouped-OR" (curly
braces might also work, but this follows the convention used
already by "git stash").

While we're at it, let's change the <sha1> specifier in the
usage to <object>. That's what the documentation uses, and
it does actually use the regular object lookup.

Signed-off-by: Jeff King <redacted>
---
This is a followup to:

  http://thread.gmane.org/gmane.comp.version-control.git/116627

 Documentation/git-cat-file.txt |    4 ++--
 builtin-cat-file.c             |    4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/Documentation/git-cat-file.txt b/Documentation/git-cat-file.txt
index b191276..58c8d65 100644
--- a/Documentation/git-cat-file.txt
+++ b/Documentation/git-cat-file.txt

@@ -9,8 +9,8 @@ git-cat-file - Provide content or type and size information for repository objec
 SYNOPSIS
 --------
 [verse]
-'git cat-file' [-t | -s | -e | -p | <type>] <object>
-'git cat-file' [--batch | --batch-check] < <list-of-objects>
+'git cat-file' (-t | -s | -e | -p | <type>) <object>
+'git cat-file' (--batch | --batch-check) < <list-of-objects>
 
 DESCRIPTION
 -----------

diff --git a/builtin-cat-file.c b/builtin-cat-file.c
index 8fad19d..43ffe7f 100644
--- a/builtin-cat-file.c
+++ b/builtin-cat-file.c

@@ -201,8 +201,8 @@ static int batch_objects(int print_contents)
 }
 
 static const char * const cat_file_usage[] = {
-	"git cat-file [-t|-s|-e|-p|<type>] <sha1>",
-	"git cat-file [--batch|--batch-check] < <list_of_sha1s>",
+	"git cat-file (-t|-s|-e|-p|<type>) <object>",
+	"git cat-file (--batch|--batch-check) < <list_of_objects>",
 	NULL
 };
 

-- 
1.6.3.1.250.g01b8b.dirty