Markup adjustments for consistency.

Doc/lib/libsmtplib.tex

@@ -178,12 +178,13 @@ or may raise the following exceptions:
 \end{description}
 \end{methoddesc}
 
-\begin{methoddesc}{starttls}{\optional{keyfile, certfile}}
-Put the SMTP connection in TLS (Transport Layer Security) mode. All SMTP
-commands that follow will be encrypted. You should then call ehlo() again.
+\begin{methoddesc}{starttls}{\optional{keyfile\optional{, certfile}}}
+Put the SMTP connection in TLS (Transport Layer Security) mode.  All
+SMTP commands that follow will be encrypted.  You should then call
+\method{ehlo()} again.
 
-If \var{keyfile} and \var{certfile} are provided, these are passed to the
-socket module's ssl function.
+If \var{keyfile} and \var{certfile} are provided, these are passed to
+the \refmodule{socket} module's \function{ssl()} function.
 \end{methoddesc}
 
 \begin{methoddesc}{sendmail}{from_addr, to_addrs, msg\optional{,