In evp.h rev. 1.109 and 1.112, jsing@ and tb@ provided

In evp.h rev. 1.109 and 1.112, jsing@ and tb@ provided
EVP_PKEY_new_raw_private_key(3), EVP_PKEY_new_raw_public_key(3),
EVP_PKEY_get_raw_private_key(3), and EVP_PKEY_get_raw_public_key(3).

Merge the documentation from the OpenSSL 1.1.1 branch, which is
still under a free license.  I tweaked the text somewhat for
conciseness, and argument names for uniformity.