Update garbage_collector.md

Author: LamentXU123

InternalDocs/garbage_collector.md

@@ -286,7 +286,7 @@ object, the GC does not process it twice.
 
 Notice that an object that was marked as "tentatively unreachable" and was later
 moved back to the reachable list will be visited again by the garbage collector
-as now all the references that that object has need to be processed as well. This
+as now all the references that object has need to be processed as well. This
 process is really a breadth first search over the object graph. Once all the objects
 are scanned, the GC knows that all container objects in the tentatively unreachable
 list are really unreachable and can thus be garbage collected.