Merge topic 'fix-project-license-doc' into release-4.2

6500ea2776 Help: Add missing gate for project(SPDX_LICENSE)

Acked-by: Kitware Robot <[email protected]>
Acked-by: buildbot <[email protected]>
Merge-request: !11342

Help/command/project.rst

@@ -109,6 +109,9 @@ The options are:
 
 ``SPDX_LICENSE <license-string>``
   .. versionadded:: 4.2
+  .. note::
+
+    Experimental. Gated by ``CMAKE_EXPERIMENTAL_EXPORT_PACKAGE_INFO``.
 
   Optional.
   Sets the variables