Merge pull request swiftlang#35989 from zoecarver/cxx/gardening/add-requires-cplusplus

[nfc][gardening] Add requires cplusplus to LinkedRecords module.

Author: zoecarver

test/Interop/Cxx/class/Inputs/module.modulemap

@@ -65,4 +65,5 @@ module NestedRecords {
 
 module LinkedRecords {
   header "linked-records.h"
+  requires cplusplus
 }