[3.9] [doc] Fix erroneous backslashes in signatures and names (GH-23658) (GH-23827)

[3.9] [doc] Fix erroneous backslashes in signatures and names (GH-23658) (GH-23827)

The issue being resolved is shown in the 3.10 docs (if you select docs for older versions you won't see a visual glitch).

The newer sphinx version that produces the 3.10 docs doesn't treat the backslash to escape things in some situations it previously did..
(cherry picked from commit dcc997cd28ab33ebac44182ee55533c1b37689f7)

Co-authored-by: Andre Delfino <adelfino@gmail.com>