fix error message for vertex struct input

Vertex shaders can have pipeline inputs that are arrays, but not structure
inputs. (GLSL 4.5 section 4.3.4)

But the error message for struct inputs says "cannot be a structure or array".
This PR removes the "or array" part.

Note: The array case is handled immediately after the check for
structure type.

Co-authored-by: Arcady Goldmints-Orlov <arcady@lunarg.com>

glslang/MachineIndependent/ParseHelper.cpp

@@ -4013,7 +4013,7 @@ void TParseContext::globalQualifierTypeCheck(const TSourceLoc& loc, const TQuali
         switch (language) {
         case EShLangVertex:
             if (publicType.basicType == EbtStruct) {
-                error(loc, "cannot be a structure or array", GetStorageQualifierString(qualifier.storage), "");
+                error(loc, "cannot be a structure", GetStorageQualifierString(qualifier.storage), "");
                 return;
             }
             if (publicType.arraySizes) {