doc txt & -h consistency: word-wrap

Change the documentation and -h output for those built-in commands
where both the -h output and *.txt were lacking in word-wrapping.

There are many more built-ins that could use this treatment, this
change is narrowed to those where this whitespace change is needed to
make the -h and *.txt consistent in the end.

In the case of "Documentation/git-hash-object.txt" and
"builtin/hash-object.c" this is not a "doc txt & -h consistency"
change, as we're changing both versions, doing so here makes a
subsequent change smaller.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/show-ref.c

@@ -9,7 +9,9 @@
 #include "parse-options.h"
 
 static const char * const show_ref_usage[] = {
-	N_("git show-ref [-q | --quiet] [--verify] [--head] [-d | --dereference] [-s | --hash[=<n>]] [--abbrev[=<n>]] [--tags] [--heads] [--] [<pattern>...]"),
+	N_("git show-ref [-q | --quiet] [--verify] [--head] [-d | --dereference]\n"
+	   "             [-s | --hash[=<n>]] [--abbrev[=<n>]] [--tags]\n"
+	   "             [--heads] [--] [<pattern>...]"),
 	N_("git show-ref --exclude-existing[=<pattern>]"),
 	NULL
 };