sync_win.v : Add a Missing Closing Bracket

vlib/sync/sync_win.v

@@ -84,7 +84,7 @@ pub fn (m mut Mutex) unlock() {
         }
     }
     m.wstate = BROKEN
-
+}
 
 pub fn (m mut Mutex) destroy() {
     if m.wstate == WAIT {
@@ -92,4 +92,4 @@ pub fn (m mut Mutex) destroy() {
     }
     m.wstate = DESTROYED // setting up reference to invalid state
     C.CloseHandle(m.mx) // destroy mutex
-}
+}