Update Doc/c-api/intro.rst

Co-authored-by: Stan Ulbrych <89152624+StanFromIreland@users.noreply.github.com>

Author: Yashp002

Doc/c-api/intro.rst

@@ -309,7 +309,9 @@ complete listing.
    compile time.
 
    The *array* argument must be a C array with a size known at compile time,
-   not a pointer. Using this macro with a pointer will produce incorrect results.
+   not a pointer. On supported compilers, passing a pointer will result in a
+   compilation error, otherwise, using this macro with a pointer will
+   produce incorrect results.
 
    This is generally equivalent to::