backend/regex.md

@@ -5,3 +5,4 @@
 * ``|`` is OR
 * ``?`` used for not greedy expression
 * ``(.*?)`` any characters in expression
+* ``[\\u10000-\\uEFFFF]`` find all UTF-16 character encodings (includes a-z, the Chinese and Greek alphabet etc.) 
\ No newline at end of file