docs: fix outdated comment on rebuild debounce behaviour

quartz/build.ts

@@ -135,7 +135,6 @@ async function rebuildFromEntrypoint(
     toRebuild,
     toRemove,
     trackedAssets,
-    lastBuildMs,
   } = buildData
 
   const { argv } = ctx
@@ -164,12 +163,12 @@ async function rebuildFromEntrypoint(
     toRemove.add(filePath)
   }
 
-  // debounce rebuilds every 250ms
-
   const buildStart = new Date().getTime()
   buildData.lastBuildMs = buildStart
   const release = await mut.acquire()
-  if (lastBuildMs > buildStart) {
+
+  // there's another build after us, release and let them do it
+  if (buildData.lastBuildMs > buildStart) {
     release()
     return
   }