doc: fix reference to --ignore-submodules

Signed-off-by: Alex Henrie <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: alexhenrie

Documentation/gitmodules.txt

@@ -90,7 +90,7 @@ of the superproject, the setting there will override the one found in
 .gitmodules.
 
 Both settings can be overridden on the command line by using the
-"--ignore-submodule" option. The 'git submodule' commands are not
+"--ignore-submodules" option. The 'git submodule' commands are not
 affected by this setting.
 --