Merge topic 'doc-project-include-vars-3.29'

dcb894fb00 Help: Update project() code injection for new 3.29 include behavior
09cf39ab07 Help: Improve wording of CMAKE_PROJECT_..._INCLUDE... changes for 3.29

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !9343