[ConstraintSystem] Switch "missing conformance" fix/diagnostic to use protocol type

Switch type allows "missing conformance" diagnostic to be
used not only for protocols by for protocol compositions as well.

lib/Sema/CSSimplify.cpp

@@ -3347,8 +3347,9 @@ ConstraintSystem::SolutionKind ConstraintSystem::simplifyConformsToConstraint(
           return SolutionKind::Error;
       }
 
-      auto *fix = MissingConformance::create(*this, type, protocol,
-                                             getConstraintLocator(locator));
+      auto *fix =
+          MissingConformance::create(*this, type, protocol->getDeclaredType(),
+                                     getConstraintLocator(locator));
       if (!recordFix(fix))
         return SolutionKind::Solved;
     }