Merge pull request #4661 from driesvints/patch-1

[5.6] Fix alpha_dash

resources/lang/en/validation.php

@@ -18,7 +18,7 @@ return [
     'after'                => 'The :attribute must be a date after :date.',
     'after_or_equal'       => 'The :attribute must be a date after or equal to :date.',
     'alpha'                => 'The :attribute may only contain letters.',
-    'alpha_dash'           => 'The :attribute may only contain letters, numbers, and dashes.',
+    'alpha_dash'           => 'The :attribute may only contain letters, numbers, dashes and underscores.',
     'alpha_num'            => 'The :attribute may only contain letters and numbers.',
     'array'                => 'The :attribute must be an array.',
     'before'               => 'The :attribute must be a date before :date.',