Variable references in interpolated strings with ${var} generate bad code

[snoopyjc]

Variable references in interpolated strings with ${var} generate bad code. For example:

$tmdate = "${year}_${month}_${day}";

produces:

tmdate=f"{[year]}_{[month]}_{[day]}"

instead of:

tmdate=f"{year}_{month}_{day}"

[snoopyjc]

Fixed in https://github.com/snoopyjc/pythonizer