Add notes about command modes and nativecomp interaction

* doc/lispref/commands.texi (Command Modes): Note interaction with
native-compile (bug#54437).

* src/data.c: Add comment about not being supported.

Do not merge to master.

doc/lispref/commands.texi

@@ -682,6 +682,11 @@ different ways (e.g., @code{eww-open-in-new-buffer} and
 mode-specific, as they can be issued by the user from pretty much any
 context.
 
+Note that specifying command modes is not supported in native-compiled
+functions in Emacs 28.1 (but this is fixed in later Emacs versions).
+This means that @code{read-extended-command-predicate} isn't supported
+in native-compile builds, either.
+
 @node Generic Commands
 @subsection Select among Command Alternatives
 @cindex generic commands

src/data.c

@@ -1022,6 +1022,9 @@ Value, if non-nil, is a list (interactive SPEC).  */)
   return Qnil;
 }
 
+/* Note that this doesn't work for native-compiled functions in Emacs
+   28.1, but it's fixed in later Emacs versions. */
+
 DEFUN ("command-modes", Fcommand_modes, Scommand_modes, 1, 1, 0,
        doc: /* Return the modes COMMAND is defined for.
 If COMMAND is not a command, the return value is nil.