Suffixes are "Not documented" after invocation from a prefix

[aurtzy]

Issue

A suffix command's documentation is no longer accessible after the command is executed from a prefix.

Expectation

To be able to see a suffix's documentation after executing it.

I found that this was not an issue in earlier versions, and was able to do a bisect (results below).

Reproduction steps

Emacs version: 29.4

Tested with emacs -Q.

1. Evaluate the following code:

   (require 'transient)
   
   (transient-define-suffix test-command ()
     "This is documentation for `test-command'."
     (interactive)
     (message "hi!"))
   
   (transient-define-prefix test-dispatch ()
     ["Test"
      ("t" "Test command" test-command)])

2. See that when executing M-x test-dispatch C-h t, documentation can be found.
3. Resume transient command with q.
4. Execute test-command with t.
5. See that executing M-x test-dispatch C-h t now displays "Not documented" in the help buffer instead of the docstring.

Bisect results

possible first bad commit: [8806655] transient-help: Fix regression
possible first bad commit: [87f70af] Use defvar-keymap
possible first bad commit: [c2bdf7e] transient--recursive-edit: Fix trivial bug
possible first bad commit: [a177418] Remove broken transient-define-groups
possible first bad commit: [5a1b2ba] Support using recursive-edit while transient is active
possible first bad commit: [fcdeadc] Support using top-level while transient is active
possible first bad commit: [52cac9c] Adjust around advice to work in Emacs < 30
possible first bad commit: [51c68c8] Use around advice to deal with skipped post-command-hook

Some of these commits had funky behavior with executing C-h in a prefix, which was fixed by the last "potentially bad" commit.

[tarsius]

This seems to be an Emacs bug, I can reproduce it like so:

(defun an-interpreted-function () nil)
(put 'an-interpreted-function 'function-documentation "The docstring.")

(let ((advice (lambda (fn &rest args)
                (apply fn args))))
  (advice-add 'an-interpreted-function :around advice)
  (advice-remove 'an-interpreted-function advice))