standardize usage info string format

This patch puts the usage info strings that were not already in docopt-
like format into docopt-like format, which will be a litle easier for
end users and a lot easier for translators. Changes include:

- Placing angle brackets around fill-in-the-blank parameters
- Putting dashes in multiword parameter names
- Adding spaces to [-f|--foobar] to make [-f | --foobar]
- Replacing <foobar>* with [<foobar>...]

Signed-off-by: Alex Henrie <alexhenrie24@gmail.com>
Reviewed-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/add.c

@@ -19,7 +19,7 @@
 #include "argv-array.h"
 
 static const char * const builtin_add_usage[] = {
-	N_("git add [options] [--] <pathspec>..."),
+	N_("git add [<options>] [--] <pathspec>..."),
 	NULL
 };
 static int patch_interactive, add_interactive, edit_interactive;