Fix rubocop complaints

Author: mbj

spec/unit/mutant/ast/pattern_spec.rb

@@ -170,23 +170,23 @@ def apply
     end
 
     context 'example from docs' do
-      let(:string) { <<~EOS }
+      let(:string) { <<~EXAMPLE }
         block
           { receiver = send
             { selector = log
               receiver = send{selector=logger}
             }
           }
-      EOS
+      EXAMPLE
 
       let(:expected_node) do
         Mutant::AST::Pattern::Node.new(
           type:       :block,
           descendant: Mutant::AST::Pattern::Node::Descendant.new(
             name:    :receiver,
             pattern: Mutant::AST::Pattern::Node.new(
-              type:      :send, 
-              attribute: Mutant::AST::Pattern::Node::Attribute.new(
+              type:       :send,
+              attribute:  Mutant::AST::Pattern::Node::Attribute.new(
                 name:  :selector,
                 value: Mutant::AST::Pattern::Node::Attribute::Value::Single.new(value: :log)
               ),
@@ -197,7 +197,7 @@ def apply
                   attribute: Mutant::AST::Pattern::Node::Attribute.new(
                     name:  :selector,
                     value: Mutant::AST::Pattern::Node::Attribute::Value::Single.new(value: :logger)
-                  ),
+                  )
                 )
               )
             )