Commit Briefs
remame sendfile to send_file and senddir to send_dir
apparently, on some systems there is a sendfile(2), so to avoid a name clash we rename it to send_file and send_dir.
explicitly require TLS 1.2 or 1.3
it's the default, but just in case (since gemini spec explicitly talks about 1.3 as "default" and 1.2 for ease of implementation)
fix errors in manpage
man -Tlint -l gmid.1 helped a lot