docs(manual): remove duplicated CFunction properties #789

Job	Run time
Build tarball distribution	25s
Build PDF document	1m 40s
Build HTML document	1m 54s
Build tform on ubuntu-24.04-arm	49s
Build form on ubuntu-24.04	1m 9s
Build tform on ubuntu-24.04	56s
Build tform on macos-15-intel	1m 25s
Build form on macos-15-intel	1m 43s
Build tform on macos-14	1m 5s
Build form on macos-14	54s
Build tform on windows-2022	2m 52s
Build form on windows-2022	2m 52s
Build form on ubuntu-24.04-arm	46s
Publish binaries to GitHub Releases	1m 20s
	19m 50s

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