bug#33921: 27.0.50; Default height is inconsistently - and apparently also incorrectly - documented

[martin rudalics]

>> The value of evaluating (frame-height) should be 36 if nothing special
>> has been specified.
>
> That's definitely not true for TTY frames.

I mentioned the GUI restriction a few lines below.

> Fine with me, but I'd be very surprised if we conclude that 36 is an
> accurate number in enough situations to cite it in the manual.

It's a default we specify explicitly.  When OS or WM interfere all
bets are off obviously.

martin