0.51.1

A dropped connection says so in a sentence.

Fixed

• AgentError.connection carries a sentence, never an error dump. HTTPClient used to put String(describing:) of the transport error in it, so a send that dropped on a cellular network read Not sent — Connection error: Error Domain=NSURLErrorDomain Code=-1005 … UserInfo={_kCFStreamErrorCodeKey=-4, …} and a connect screen read Unreachable: Error Domain=…. TransportWords.sentence(for:) names the situation (the connection dropped, the server took too long, this device is offline, nothing is answering at that address, the address could not be found, no secure connection, an unreadable answer) in all ten languages, for URLError on every platform and for AsyncHTTPClient and SwiftNIO errors on Linux; the error itself goes to the http log. Retryability is unchanged.
• "The server can't be reached right now." is translated.