[Fix #12862] Fix a false positive for Style/RedundantLineContinuation

Fixes #12862.

This PR fixes a false positive for `Style/RedundantLineContinuation`
when line continuations involve `return` with a return value.

Author: koic

changelog/fix_false_positive_for_style_redundant_line_continuation.md

@@ -0,0 +1 @@
+* [#12862](https://github.com/rubocop/rubocop/issues/12862): Fix a false positive for `Style/RedundantLineContinuation` when line continuations involve `return` with a return value. ([@koic][])

lib/rubocop/cop/style/redundant_line_continuation.rb

@@ -137,7 +137,9 @@ def inside_string_literal?(range, token)
         #   do_something \
         #     argument
         def method_with_argument?(current_token, next_token)
-          current_token.type == :tIDENTIFIER && ARGUMENT_TYPES.include?(next_token.type)
+          return false if current_token.type != :tIDENTIFIER && current_token.type != :kRETURN
+
+          ARGUMENT_TYPES.include?(next_token.type)
         end
 
         # rubocop:disable Metrics/AbcSize

spec/rubocop/cop/style/redundant_line_continuation_spec.rb

@@ -114,6 +114,28 @@ def self.foo(bar,#{trailing_whitespace}
     RUBY
   end
 
+  it 'does not register an offense when line continuations involve `return` with a return value' do
+    expect_no_offenses(<<~'RUBY')
+      return \
+        foo
+    RUBY
+  end
+
+  it 'registers an offense when line continuations involve `return` with a parenthesized return value' do
+    expect_offense(<<~'RUBY')
+      return(\
+             ^ Redundant line continuation.
+        foo
+      )
+    RUBY
+
+    expect_correction(<<~RUBY)
+      return(
+        foo
+      )
+    RUBY
+  end
+
   it 'registers an offense when line continuations with `if`' do
     expect_offense(<<~'RUBY')
       if foo \