They are still used internally in legacy code.

Also fixed up some minor things in EVP_DigestInit.pod

Fixes: #14003
Reviewed-by: NRichard Levitte <levitte@openssl.org>
Reviewed-by: NPaul Dale <pauli@openssl.org>
Reviewed-by: NTomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/14008)