doc txt & -h consistency: use "<options>", not "<options>..."

It's arguably more correct to say "[<option>...]" than either of these
forms, but the vast majority of our documentation uses the
"[<options>]" form to indicate an arbitrary number of options, let's
do the same in these cases, which were the odd ones out.

In the case of "mv" and "sparse-checkout" let's add the missing "[]"
to indicate that these are optional.

In the case of "t/helper/test-proc-receive.c" there is no *.txt
version, making it the only hunk in this commit that's not a "doc txt
& -h consistency" change.

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

t/helper/test-proc-receive.c

@@ -6,7 +6,7 @@
 #include "test-tool.h"
 
 static const char *proc_receive_usage[] = {
-	"test-tool proc-receive [<options>...]",
+	"test-tool proc-receive [<options>]",
 	NULL
 };