The previous attempt removed the TLSv1.3 version for the
"ciphersuites" keywords. However it looks like the TLSv1.2 support for
SSL_CTX_set_ciphersuites() is a bug, and can have inconsistent behavior.
This patch revert the previous attempt and add explaining about this
problem and clear examples on how to configure TLSv1.2 ciphers + TLSv1.3
ciphersuites.
Revert "DOC: configuration: clarify ciphersuites usage"
This reverts commit e2a44d6c94b08d1bdf6294706c3b64267a13c86f.
This must be backported to all stable branches.
Fixes issue #2459.