Fix an error for Layout/HeredocArgumentClosingParenthesis

This PR fixes an error for `Layout/HeredocArgumentClosingParenthesis`
when heredoc is a method argument in a parenthesized block argument:

```ruby
foo(bar do
  baz <<~EOS
  EOS
end)
```

```console
% bundle exec rubocop --only Layout/HeredocArgumentClosingParenthesis
(snip)

undefined method `begin_pos' for nil:NilClass
/Users/koic/src/github.com/rubocop/rubocop/lib/rubocop/cop/layout/
heredoc_argument_closing_parenthesis.rb:220:in `exist_argument_between_heredoc_end_and_closing_parentheses?'
/Users/koic/src/github.com/rubocop/rubocop/lib/rubocop/cop/layout/
heredoc_argument_closing_parenthesis.rb:73:in `on_send'
/Users/koic/src/github.com/rubocop/rubocop/lib/rubocop/cop/commissioner.rb:107:in `public_send'
```

changelog/fix_an_error_for_layout_heredoc_argument_closing_parenthesis.md

@@ -0,0 +1 @@
+* [#11579](https://github.com/rubocop/rubocop/pull/11579): Fix an error for `Layout/HeredocArgumentClosingParenthesis` when heredoc is a method argument in a parenthesized block argument. ([@koic][])

lib/rubocop/cop/layout/heredoc_argument_closing_parenthesis.rb

@@ -215,6 +215,7 @@ def incorrect_parenthesis_removal_end(node)
         end
 
         def exist_argument_between_heredoc_end_and_closing_parentheses?(node)
+          return true unless node.loc.end
           return false unless (heredoc_end = find_most_bottom_of_heredoc_end(node.arguments))
 
           heredoc_end < node.loc.end.begin_pos &&

spec/rubocop/cop/layout/heredoc_argument_closing_parenthesis_spec.rb

@@ -76,6 +76,16 @@
       RUBY
     end
 
+    it 'accepts when heredoc is a method argument in a parenthesized block argument' do
+      expect_no_offenses(<<~RUBY)
+        foo(bar do
+          baz <<~EOS
+            text
+          EOS
+        end)
+      RUBY
+    end
+
     it 'accepts correct case with other param after' do
       expect_no_offenses(<<~RUBY)
         foo(<<-SQL, 123)