The fmt::format() function looks for the "{arg}" named argument
in the given "format" string which does not exist. It will fail
if the string contains any {...} curled-brace substring.
Consequently, any "on-click*" option's command line containing for
instance substring like "${var}" or "awk '{...}'" will crash the program.
Signed-off-by: Thomas Venriès <thomas.venries@gmail.com>
Jordi Pakey-Rodriguez
Thomas Venriès
Patrick Hilhorst
Alex