Documentation around secured vs. unsecured proxies

[shutton]

The documentation around what comprises a "Secured" vs "Regular" proxy is a bit thin. I was trying to track down some issues around the fact that I use a proxy wrapper whether or not a proxy is in use (which keeps our types a bit simpler -- we just create a proxy with Intercept::None set and provide a bogus proxy server). But if you do this without using the from_proxy_unsecured ProxyConnector constructor, a BadDER error gets thrown.

Obviously, I fixed my particular implementation, but the documentation for both ProxyConnector::from_proxy and ProxyConnector::from_proxy_unsecured is the same ("Create a proxy connector and attach a particular proxy").