In Network::capAvailable(), fix typo of "guarentee" -> "guarantee".
This doesn't have any impact on running code, but should still be
fixed.
Thanks to @justJanne for finding this.
Closes GH-300.
*
* These results aren't valid if the network is disconnected or capability negotiation hasn't
* happened, and some servers might not correctly advertise capabilities. Don't treat this as
- * a guarentee.
+ * a guarantee.
*
* @param[in] capability Name of capability
* @returns True if connected and advertised by the server, otherwise false