git-sparse-checkout.txt: add missing '

Where we explain the 'reapply' command, we don't properly wrap it in
single quote marks like we do with the other commands: We omit the
closing mark ("'reapply") and this ends up being rendered literally as
"'reapply". Add the missing "'".

Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: Martin Ågren

Documentation/git-sparse-checkout.txt

@@ -70,7 +70,7 @@ C-style quoted strings.
 	`core.sparseCheckoutCone` is enabled, the given patterns are interpreted
 	as directory names as in the 'set' subcommand.
 
-'reapply::
+'reapply'::
 	Reapply the sparsity pattern rules to paths in the working tree.
 	Commands like merge or rebase can materialize paths to do their
 	work (e.g. in order to show you a conflict), and other