order of chains affecting interactor creation

[rvhonorato]

when creating true interface restraints, the target.id is supposed to match the position of the chain in the pdb

haddock-restraints/src/main.rs

Lines 246 to 248 in ea53978

	if let Some(target_index) = pdb.chains().position(|chain| chain.id() == *target_chain) {
	interactor.add_target(target_index as u16);
	}

This works fine if the chains are in the pdb as A-B but will fail to match if B-A