Deleted constructors

libsemigroups::CongruenceByPairs::CongruenceByPairs() = delete

A CongruenceByPairs instance is not default-constructible. This constructor is deleted.

CongruenceByPairs &libsemigroups::CongruenceByPairs::operator=(CongruenceByPairs const&) = delete

A CongruenceByPairs instance is not copy assignable. This constructor is deleted.

CongruenceByPairs &libsemigroups::CongruenceByPairs::operator=(CongruenceByPairs&&) = delete

A CongruenceByPairs instance is not move assignable. This constructor is deleted.