[3.11] gh-101100: [Enum] Fix sphinx warnings in docs (GH-101122) (#101173)

(cherry picked from commit 9e025d305f159aebf01775ad1dc2817679f01aa9)

Co-authored-by: Nikita Sobolev <mail@sobolevn.me>
Co-authored-by: C.A.M. Gerlach <CAM.Gerlach@Gerlach.CAM>
1 file changed