crypt.3, encrypt.3: Fix library name and description

crypt.3, encrypt.3: Fix library name and description

libcrypt is the password hashing library, and libcrypto is a completely
different library (OpenSSL cryptography library).  While the encrypt()
function can "encrypt" things, it uses a broken algorithm so let's not
call libcrypt an "encryption" library at all.  In crypt.3, also replace
"encrypt" with "hash" except several places where it really means
"encrypt".

Signed-off-by: Xi Ruoyao <xry111@xry111.site>
Signed-off-by: Alejandro Colomar <alx@kernel.org>