bug#45437: 27.1; make-temp-file parameter change in emacs 26 missing in documentation

[Hendrik Tews]

Hi,

the function make-temp-file was extended in emacs 26 with the
additional optional TEXT argument. However, describe-function
says "Probably introduced at or before Emacs version 21.1.",
leaving the impression that one can safely use the TEXT argument
if one wants to write backward compatible code.

Please amend the documentation of make-temp-file to mention that
the TEXT argument was added in emacs 26. Without such
information, it is very difficult to write code that works in a
variety of emacs major versions.

Thanks,

Hendrik