explain the monkey patching

Author: Will Fleming

lib/rubocop/cop/method_complexity_patch.rb

@@ -2,6 +2,14 @@
 module RuboCop
   module Cop
     module MethodComplexity
+      # RuboCop's default implementation of `add_offense` in `Cop` only gets the
+      # location of the keyword associated with the problem which, for things
+      # like complexity checkers, is just the method def line. This isn't very
+      # useful for checkers where the entire method body is relevant. Fetching
+      # this information from an `Offense` instance is difficult, since the
+      # original AST is no longer available. So it's easier to monkey-path
+      # this method on complexity checkers to send the location of the entire
+      # method to the created `Offense`.
       def add_offense(node, loc, message = nil, severity = nil)
         super(node, node.loc, message, severity)
       end