Add a note about references and pointers to Expression::Load (#708)

* Add a note about references and pointers to Expression::Load

* Formatting

* Remove comma

* Clearer English

src/back/msl/writer.rs

@@ -676,7 +676,9 @@ impl<W: Write> Writer<W> {
                 write!(self.out, "{}", name)?;
             }
             crate::Expression::Load { pointer } => {
-                //write!(self.out, "*")?;
+                // We don't do any dereferencing with `*` here as pointer arguments to functions
+                // are done by `&` references and not `*` pointers. These do not need to be
+                // dereferenced.
                 self.put_expression(pointer, context, is_scoped)?;
             }
             crate::Expression::ImageSample {