Add docs for key_file and cert_file arguments for HTTPSConnection. Copied from socket.ssl docs.

Doc/lib/libhttplib.tex

@@ -52,9 +52,15 @@ the server at the same host and port:
 \versionadded{2.0}
 \end{classdesc}
 
-\begin{classdesc}{HTTPSConnection}{host\optional{, port}}
+\begin{classdesc}{HTTPSConnection}{host\optional{, port, key_file, cert_file}}
 A subclass of \class{HTTPConnection} that uses SSL for communication with
 secure servers.  Default port is \code{443}.
+\var{key_file} is
+the name of a PEM formatted file that contains your private
+key. \var{cert_file} is a PEM formatted certificate chain file.
+
+\warning{This does not do any certificate verification!}
+
 \versionadded{2.0}
 \end{classdesc}