Update cached.ts

Author: NullVoxPopuli

packages/@ember/-internals/metal/lib/cached.ts

@@ -84,10 +84,9 @@ import { createCache, getValue } from '@glimmer/validator';
   the subsequent cache invalidations of the `@cached` properties who were
   using this `trackedProp`.
 
-  As a reminder, do not use this piece of code inside a tracked getter,
-  as the dependency chain could lead to an infinite loop. Mutating an adjacent
-  property from a getter is not a good practice anyway, even with a caching
-  mechanism reducing reruns.
+  Remember that setting tracked data should only be done during initialization, 
+  or as the result of a user action. Setting tracked data during render
+  (such as in a getter), is not supported.
 
   @method cached
   @static