3.4.36 `tpl-file-line' - get the template file and line number

Usage: (tpl-file-line [ msg-fmt ])
Returns the file and line number of the current template macro using either the default format, "from %s line %d", or else the format you supply. For example, if you want to insert a "C" language file-line directive, you would supply the format "# %2$d %1$s".

Arguments:
msg-fmt - Optional - formatting for line message