Resolve warning: duplicate character class in regex

Author: jas14

spec/support/integration/matchers/produce_output_when_run_matcher.rb

@@ -12,7 +12,7 @@ def initialize(expected_output)
       end
 
       def removing_object_ids
-        first_replacing(/#<([\w_:]+):0x[a-f0-9]+/, '#<\1')
+        first_replacing(/#<([\w:]+):0x[a-f0-9]+/, '#<\1')
         self
       end