Adjust signatures of BIO_ctrl functions

Adjust signatures of BIO_ctrl functions

In bio.h r1.54, the signature of BIO_callback_ctrl() was changed from
bio_info_cb to BIO_info_cb. Adjust manual to reflect this change.

At the moment, bio_info_cb and BIO_info_cb are still distinct types with
our BIO_info_cb matching OpenSSL's definition. Historically, bio_info_cb
had a different type, but that leads to issues with casting function
pointers. The ecosystem has moved on to embrace the new type and several
ports confuse the two types because OpenSSL decided to "solve" the issues
with "typedef BIO_info_cb bio_info_cb; /* backward compatibilty */". We
will align with this in the next bump.

ok jsing