Remove "Maximum number of half-open connections" as it's not used anymore

Explanation-of-Options-in-qBittorrent.mediawiki

@@ -133,7 +133,6 @@ A complete list of libtorrent configuration may be found [https://www.libtorrent
 * '''Send buffer watermark''' — this is the upper limit for the send buffer size. If the send buffer has fewer bytes than this, another 16kB block will be read into it. If set too small, upload rate capacity will suffer. If set too high, memory will be wasted. The actual watermark may be lower than this in case the upload rate is low.
 * '''Send buffer low watermark''' — the minimum send buffer target size (send buffer includes bytes pending being read from disk). For good and snappy seeding performance, set this fairly high, to at least fit a few blocks. This is essentially the initial window size which will determine how fast we can ramp up the send rate.
 * '''Send buffer watermark factor''' — the factor is specified as a percentage. i.e. 50 -> 0.5. The current upload rate to a peer is multiplied by this factor to get the send buffer watermark. This product is clamped to the "Send buffer watermark" setting so as to not exceed the max. For high speed upload, this should be set to a greater value than 100. For high capacity connections, setting this higher can improve upload performance and disk throughput. Setting it too high may waste RAM and create a bias towards read jobs over write jobs.
-* '''Maximum number of half-open connections''' —  sets the maximum number of half-open connections libtorrent will have when connecting to peers.  A half-open connection is one where connect() has been called, but the connection still hasn't been established (nor failed).
 * '''Outgoing ports''' — this is the range of ports to use for binding outgoing connections to and it shouldn't be too small. It is useful for users that have routers that allow QoS settings based on local port. Setting outgoing ports will limit the ability to keep multiple connections to the same client, even for different torrents. It is not recommended to change this setting. Its main purpose is to use it as an escape hatch for cheap routers with QoS capability but can only classify flows based on port numbers. It is a range instead of a single port because of the problems with failing to reconnect to peers if a previous socket to that peer and port is in the waiting state.
 * '''µTP-TCP mixed mode algorithm''' — determines how to treat TCP connections when there are uTP connections.  Since uTP is designed to yield to TCP, there's an inherent problem when using swarms that have both TCP and uTP connections. If nothing is done, uTP connections would often be starved out for bandwidth by the TCP connections. This mode is called "Prefer TCP" in qBittorrent. The "Peer proportional" mode on the other hand, simply looks at the current throughput and rate limits all TCP connections to their proportional share based on how many of the connections are TCP. This works best if uTP connections are not rate limited by the global rate limiter.
 * '''Allow multiple connections from the same IP address''' — determines if connections from the same IP address as existing onnections should be rejected or not.  This option is disabled by default to prevent abusive behavior by peers.  It may be useful to allow such connections in cases where simulations are run on the same machine, and all peers in a swarm has the same IP address.