add quotes around object name

Author: kparzysz

flang/lib/Semantics/check-omp-structure.cpp

@@ -4550,7 +4550,7 @@ void OmpStructureChecker::CheckIfContiguous(const parser::OmpObject &object) {
     const parser::Name *name{GetObjectName(object)};
     assert(name && "Expecting name component");
     context_.Say(name->source,
-        "Reference to %s must be a contiguous object"_err_en_US,
+        "Reference to '%s' must be a contiguous object"_err_en_US,
         name->ToString());
   }
 }

flang/test/Semantics/OpenMP/from-clause-v45.f90

@@ -2,7 +2,7 @@
 
 subroutine f00(x)
   integer :: x(10)
-!ERROR: Reference to x must be a contiguous object
+!ERROR: Reference to 'x' must be a contiguous object
   !$omp target update from(x(1:10:2))
 end
 

flang/test/Semantics/OpenMP/reduction06.f90

@@ -8,21 +8,21 @@ program omp_reduction
   integer :: k = 10
   integer :: a(10), b(10,10,10)
 
-  !ERROR: Reference to a must be a contiguous object
+  !ERROR: Reference to 'a' must be a contiguous object
   !$omp parallel do reduction(+:a(1:10:3))
   do i = 1, 10
     k = k + 1
   end do
   !$omp end parallel do
 
-  !ERROR: Reference to b must be a contiguous object
+  !ERROR: Reference to 'b' must be a contiguous object
   !$omp parallel do reduction(+:b(1:10:3,1:8:1,1:5:1))
   do i = 1, 10
     k = k + 1
   end do
   !$omp end parallel do
 
-  !ERROR: Reference to b must be a contiguous object
+  !ERROR: Reference to 'b' must be a contiguous object
   !$omp parallel do reduction(+:b(1:10:1,1:8:2,1:5:1))
   do i = 1, 10
     k = k + 1

flang/test/Semantics/OpenMP/to-clause-v45.f90

@@ -2,7 +2,7 @@
 
 subroutine f00(x)
   integer :: x(10)
-!ERROR: Reference to x must be a contiguous object
+!ERROR: Reference to 'x' must be a contiguous object
   !$omp target update to(x(1:10:2))
 end