filter before add --error-format

[scturtle]

To work around error: Option 'error-format' given more than once.

[Xanewok]

IIRC that's to work around --error-format being passed with CARGO_PIPELINING (?) enabled in Cargo, no?

I think it'd be good to extract a helper function that does that since it's not immediately obvious what's happening and why. Could you extract a function that given the arguments and the key to skip (--error-format in this case) returns the new arguments instead? I think it'd help with readability, also with a comment on why we have to do that.

[Xanewok]

cc #1484