bug#62086: 29.0.60; ruby-ts-mode regressions

[Juri Linkov]

>> I don't know if the second bug is related to this, but while
>> in the same file, also type 'C-M-l' ('reposition-window').
>> It raises the error:
>>
>>   Debugger entered--Lisp error: (wrong-type-argument number-or-marker-p nil)
>>     treesit-end-of-defun()
>>     end-of-defun(-1)
>>     reposition-window(nil nil)
>>     reposition-window(nil 89)
>>     funcall-interactively(reposition-window nil 89)
>>     command-execute(reposition-window)
>>
>> This regression is also recent.
>
> I seem to unable to reproduce this.  Maybe it happens only in some
> particular place in the file?

It happens everywhere in that file with ruby-ts-mode in 'emacs-29 -Q'.
To get the backtrace, I set debug-on-error to t.