Fix link for pattern char filter

Closes elastic#294

Author: ebuildy

260_Synonyms/70_Symbol_synonyms.asciidoc

@@ -64,4 +64,4 @@ have used real words, like `happy` and `sad`.
 TIP: The `mapping` character filter is useful for simple replacements of exact
 character sequences. ((("mapping character filter", "replacements of exact character sequences")))For more-flexible pattern matching, you can use regular
 expressions with the
-http://bit.ly/1ICF5bB[`pattern_replace` character filter].
+http://bit.ly/1DK4hgy[`pattern_replace` character filter].