GlobalAPI: clarify key path behavior

Author: ikonst

website/versioned_docs/version-29.7/GlobalAPI.md

@@ -250,7 +250,7 @@ Use `describe.each` if you keep duplicating the same test suites with different
     - `%#` - Index of the test case.
     - `%%` - single percent sign ('%'). This does not consume an argument.
   - Or generate unique test titles by injecting properties of test case object with `$variable`
-    - To inject nested object values use you can supply a keyPath i.e. `$variable.path.to.value`
+    - To inject nested object values use you can supply a keyPath i.e. `$variable.path.to.value` (only works for ["own" properites](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/hasOwnProperty), e.g. `$obj.constructor.name` wouldn't work)
     - You can use `$#` to inject the index of the test case
     - You cannot use `$variable` with the `printf` formatting except for `%%`
 - `fn`: `Function` the suite of tests to be run, this is the function that will receive the parameters in each row as function arguments.