git-remote-mediawiki: change style in a regexp

In this regexp, ' |\n' is used, whereas its equivalent '[ \n]', which is
clearer, is used elsewhere. Make the style coherent.

Signed-off-by: Célestin Matte <celestin.matte@ensimag.fr>
Signed-off-by: Matthieu Moy <matthieu.moy@grenoble-inp.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/mw-to-git/git-remote-mediawiki.perl

@@ -1192,7 +1192,7 @@ sub mw_push_revision {
 		my @history = split(/\n/, $history);
 		@history = @history[1..$#history];
 		foreach my $line (reverse @history) {
-			my @commit_info_split = split(/ |\n/, $line);
+			my @commit_info_split = split(/[ \n]/, $line);
 			push(@commit_pairs, \@commit_info_split);
 		}
 	}