beautify_urlpath: add ./ before checking for /index.html

This fixes a bug: when a page links to its own #comments anchor you would
get a link like "index.html#comments" rather than "./#comments".

IkiWiki.pm

@@ -949,16 +949,16 @@ sub formattime ($;$) {
 sub beautify_urlpath ($) {
 	my $url=shift;
 
-	if ($config{usedirs}) {
-		$url =~ s!/index.$config{htmlext}$!/!;
-	}
-
 	# Ensure url is not an empty link, and if necessary,
 	# add ./ to avoid colon confusion.
 	if ($url !~ /^\// && $url !~ /^\.\.\//) {
 		$url="./$url";
 	}
 
+	if ($config{usedirs}) {
+		$url =~ s!/index.$config{htmlext}$!/!;
+	}
+
 	return $url;
 }