Deal with Discord RPC using a port other than 6463

[keysmashes]

Discord can start its RPC server on any port from 6463 to 6472 (inclusive), if the lower ports are already in use, so we should probably somehow handle this properly rather than just trying port 6463 only.

Note that this can behave annoyingly if e.g. you open Discord client A (and it claims port 6463) then open client B (which claims 6464), then close client A – client B will continue to use 6464 even though 6463 is no longer in use.

[keysmashes]

something like this is probably a decent approach