perf(theme/search): prevent repeated rendering of same page (#2398)

src/client/theme-default/components/VPLocalSearchBox.vue

@@ -155,6 +155,9 @@ debouncedWatch(
     if (canceled) return
     const c = new Map<string, Map<string, string>>()
     for (const { id, mod } of mods) {
+      const mapId = id.slice(0, id.indexOf('#'))
+      let map = c.get(mapId)
+      if (map) continue
       const comp = mod.default ?? mod
       if (comp?.render) {
         const app = createApp(comp)
@@ -178,8 +181,6 @@ debouncedWatch(
         const sections = div.innerHTML.split(headingRegex)
         app.unmount()
         sections.shift()
-        const mapId = id.slice(0, id.indexOf('#'))
-        let map = c.get(mapId)
         if (!map) {
           map = new Map()
           c.set(mapId, map)