submodule-helper: fix usage string

The missing space at the end of the line makes the closing square
bracket sticking to the dash in the next line

Found during localisation v2.36.0 round 1

Signed-off-by: Fangyi Zhou <me@fangyi.io>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Fangyi Zhou
2022-04-06 21:32:57 +01:00
committed by Junio C Hamano
parent f05da2b48b
commit 5da9560ebc