Fix comment about the -enable-16bit-types flag

Author: Icohedron

llvm/lib/Target/DirectX/DXILShaderFlags.cpp

@@ -220,8 +220,9 @@ void ModuleShaderFlags::initialize(Module &M, DXILResourceTypeMap &DRTM,
     if (RMA->getValue() != 0)
       CanSetResMayNotAlias = false;
 
-  // Set UseNativeLowPrecision using the dx.nativelowprec module flag set by
-  // the command line option -enable-16bit-types
+  // NativeLowPrecision can only be set when the command line option
+  // -enable-16bit-types is provided. This is indicated by the dx.nativelowprec
+  // module flag being set
   if (auto *NativeLowPrec = mdconst::extract_or_null<ConstantInt>(
           M.getModuleFlag("dx.nativelowprec")))
     if (MMDI.ShaderModelVersion >= VersionTuple(6, 2) &&