bug#57626: 13.1.4; cases* environment doesn't let me use $

[Ikumi Keita]

>>>>> Wierdl Máté <wierdlmate@gmail.com> writes:
> In my opinion (just a longtime user's opinion), this direction of "let us
> prevent the user from making a mistake as he types" doesn't seem essential,

I feel similarly.

I began to think that `TeX-insert-dollar' should behave the same way as
in non-math mode when `texmathp' thinks that math mode didn't start with
dollar(s), possibly with a warning message.

What do others think?

Best,
Ikumi Keita
#StandWithUkraine #StopWarInUkraine