[Eva] Fixes some comments. In abstract_domain, renames Return into Result.

src/plugins/value/domains/abstract_domain.mli

src/plugins/value/domains/apron/apron_domain.ml

src/plugins/value/domains/cvalue/cvalue_domain.ml

src/plugins/value/domains/printer_domain.ml

src/plugins/value/domains/traces_domain.ml

src/plugins/value/engine/iterator.ml

src/plugins/value/engine/transfer_specification.ml