[Fix #6737] Fix an incorrect auto-correct for Rails/LinkToBlank

Fixes #6737.

This PR fixes an incorrect auto-correct for `Rails/LinkToBlank` when
`link_to` method arguments are enclosed in parentheses.

Author: koic

lib/rubocop/cop/rails/link_to_blank.rb

@@ -74,7 +74,9 @@ def append_to_rel(rel_node, corrector)
         def add_rel(send_node, offence_node, corrector)
           quote_style = offence_node.children.last.source[0]
           new_rel_exp = ", rel: #{quote_style}noopener#{quote_style}"
-          corrector.insert_after(send_node.loc.expression, new_rel_exp)
+          range = send_node.arguments.last.source_range
+
+          corrector.insert_after(range, new_rel_exp)
         end
 
         def contains_noopener?(str)

spec/rubocop/cop/rails/link_to_blank_spec.rb

@@ -59,6 +59,21 @@
           end
         RUBY
       end
+
+      it 'autocorrects with a new rel when using the block syntax ' \
+         'with parenthesis' do
+        new_source = autocorrect_source(<<-RUBY.strip_indent)
+          link_to('https://www.example.com', target: '_blank') do
+            "Click here"
+          end
+        RUBY
+
+        expect(new_source).to eq(<<-RUBY.strip_indent)
+          link_to('https://www.example.com', target: '_blank', rel: 'noopener') do
+            "Click here"
+          end
+        RUBY
+      end
     end
 
     context 'when using rel' do