3.4.34 `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 only the line number, you would supply the format "%2$d".

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