fix typo on inline comment (facebook#13364)

Author: Alex Rohleder

packages/react-reconciler/src/ReactFiberScheduler.js

@@ -1871,7 +1871,7 @@ function performSyncWork() {
 function performWork(minExpirationTime: ExpirationTime, dl: Deadline | null) {
   deadline = dl;
 
-  // Keep working on roots until there's no more work, or until the we reach
+  // Keep working on roots until there's no more work, or until we reach
   // the deadline.
   findHighestPriorityRoot();