[Fix rubocop#11949] Fix a false positive for Layout/RedundantLineBreak

Fixes rubocop#11949.

This PR fixes a false positive for `Layout/RedundantLineBreak`
when using a line broken string.

changelog/fix_a_false_positive_for_layout_redundant_line_break.md

@@ -0,0 +1 @@
+* [#11949](https://github.com/rubocop/rubocop/issues/11949): Fix a false positive for `Layout/RedundantLineBreak` when using a line broken string. ([@koic][])

lib/rubocop/cop/layout/redundant_line_break.rb

@@ -99,7 +99,7 @@ def single_line_block_chain_enabled?
         def suitable_as_single_line?(node)
           !comment_within?(node) &&
             node.each_descendant(:if, :case, :kwbegin, :def).none? &&
-            node.each_descendant(:dstr, :str).none?(&:heredoc?) &&
+            node.each_descendant(:dstr, :str).none? { |n| n.heredoc? || n.value.include?("\n") } &&
             node.each_descendant(:begin).none? { |b| !b.single_line? }
         end
 

spec/rubocop/cop/layout/redundant_line_break_spec.rb

@@ -341,6 +341,16 @@ def resolve_inheritance_from_gems(hash)
               .baz
           RUBY
         end
+
+        it 'does not register an offense with a line broken string argument' do
+          expect_no_offenses(<<~RUBY)
+            foo('
+              xyz
+            ')
+              .bar
+              .baz
+          RUBY
+        end
       end
     end