Help: Note case where IMPORTED_IMPLIB isn't needed for (xc)frameworks

Help/prop_tgt/IMPORTED_IMPLIB.rst

@@ -20,6 +20,12 @@ This property may be set:
     the library is considered to be a stub, and its location will not
     be added as a runtime search path to dependents that link it.
 
+.. versionchanged:: 3.28
+  If an imported target is an Apple framework or XCFramework, the preferred
+  arrangement is to set :prop_tgt:`IMPORTED_LOCATION` to the ``.framework``
+  or ``.xcframework`` directory.  CMake will then find the relevant ``.tbd``
+  file inside that framework or XCFramework automatically without requiring
+  ``IMPORTED_IMPLIB`` to be set.
 
 The ``IMPORTED_IMPLIB`` target property may be overridden for a
 given configuration ``<CONFIG>`` by the configuration-specific