Add comma

Author: jturner314

RELEASES.md

@@ -92,7 +92,7 @@ API changes
     implementation. Add the similar `From<&'a SliceInfo<T, Din, Dout>> for
     SliceInfo<&'a [SliceInfoElem], Din, Dout>` conversion as an alternative.
   - Change the *expr* `;` *step* case in the `s![]` macro to error at compile
-    time if an unsupported type for *expr* is used instead of panicking at
+    time if an unsupported type for *expr* is used, instead of panicking at
     runtime.
 
   https://github.com/rust-ndarray/ndarray/pull/570 <br>