bug#44349: 28.0.50; Assertion failure on macOS when resizing frame

[Eli Zaretskii]

> From: Philipp Stephani <p.stephani2@gmail.com>
> Date: Sat, 31 Oct 2020 16:57:54 +0100
> 
> > doprnt.c:493: Emacs fatal error: assertion failed: ASCII_CHAR_P (fmtchar)
> > Fatal error 6: Aborted
> > Abort trap: 6

I cannot say I understand why that assertion is there.