[Fix #1015] Make Style/InvertibleUnlessCondition aware of Active Support methods

Resolves #1015.

This PR makes `Style/InvertibleUnlessCondition` aware of Active Support methods.
It still inherits the default disabled.

Author: koic

changelog/change_make_style_invertible_unless_condition_aware_of_as_methods.md

@@ -0,0 +1 @@
+* [#1015](https://github.com/rubocop/rubocop-rails/issues/1015): Make `Style/InvertibleUnlessCondition` aware of Active Support methods. ([@koic][])

config/default.yml

@@ -1204,6 +1204,14 @@ Style/FormatStringToken:
   AllowedMethods:
     - redirect
 
+Style/InvertibleUnlessCondition:
+  InverseMethods:
+    # Active Support defines some common inverse methods. They are listed below:
+    :present?: :blank?
+    :blank?: :present?
+    :include?: :exclude?
+    :exclude?: :include?
+
 Style/SymbolProc:
   AllowedMethods:
     - define_method