Fix bug with single process refresh not working (#836)

I misunderstood the new API. It returns the number of processes still
alive, not how many got closed.

crates/livesplit-auto-splitting/src/runtime/mod.rs

@@ -136,7 +136,7 @@ impl ProcessList {
         if self
             .system
             .refresh_processes_specifics(ProcessesToUpdate::Some(&[pid]), single_process())
-            != 0
+            == 0
         {
             // FIXME: Unfortunately `refresh_process_specifics` doesn't remove
             // the process if it doesn't exist anymore. There also doesn't seem