Off-by-one error in line count / no line error

[Geod24]

It seems that line / column count starts at 0 and not 1, which might be confusing for the user.
Also, some error are not associated with a column / line (e.g. missing required key), but show as (0:0)

[Geod24]

Worked around for now. There's also an issue here, it should say /dev/null:

configy/source/configy/test.d

Lines 506 to 513 in 60e36ae

	try
	{
	auto _ = parseConfigString!Config("limits:\n reqs: 42", "/dev/null");
	}
	catch (ConfigException exc)
	{
	assert(exc.toString() == "<unknown>(1:1): chris.jay: Required key was not found in configuration or command line arguments", exc.toString());
	}