Merge pull request Textualize#5465 from Plywood9/fix-timer-busy-loop

Fix busy loop on lagging timer

src/textual/timer.py

@@ -153,7 +153,7 @@ async def _run(self) -> None:
             next_timer = start + ((count + 1) * _interval)
             now = _time.get_time()
             if self._skip and next_timer < now:
-                count += 1
+                count = int((now - start) / _interval + 1)
                 continue
             now = _time.get_time()
             wait_time = max(0, next_timer - now)