improve log when proxy type is not supported

[Itsusinn]

error: process didn't exit successfully: target\debug\clash-rs.exe --config config.yaml (exit code: 1)

[VendettaReborn]

we did not print the error msg after the failing of clash::start_scaffold

[VendettaReborn]

for unknown fields in config, i think we could derive better ways of catching all the unknown fields at once,instead of reporting the error (this is still not done yet) one by one.

[Itsusinn]

we did not print the error msg after the failing of clash::start_scaffold

we can println!("{:#}", error) as I tried last day

[Itsusinn]

for unknown fields in config, i think we could derive better ways of catching all the unknown fields at once,instead of reporting the error (this is still not done yet) one by one.

How serde handle this behavior, can we change that?