Fix problem with search term being filtered from search results

Some leftover code meant that tiddlers titled with the precise search
term were excluded from the results.

core/modules/filters/search.js

@@ -19,8 +19,7 @@ exports.search = function(source,operator,options) {
 	var invert = operator.prefix === "!";
 	return options.wiki.search(operator.operand,{
 		titles: source,
-		invert: invert,
-		exclude: [operator.operand]
+		invert: invert
 	});
 };