docs: add `lastUpdated` config

docs/config/app-configs.md

@@ -146,3 +146,16 @@ export default {
   appearance: true
 }
 ```
+
+## lastUpdated
+
+- Type: `boolean`
+- Default: `false`
+
+Use git commit to get the timestamp. Some themes may use it.
+
+```ts
+export default {
+  lastUpdated: true
+}
+```

docs/config/theme-configs.md

@@ -33,6 +33,13 @@ export default {
 }
 ```
 
+## lastUpdated
+
+- Type: `string`
+- Default: `Last Updated`
+
+The Last Updated prompt text.
+
 ## footer
 
 - Type: `Footer`

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

@@ -18,7 +18,7 @@ onMounted(() => {
 
 <template>
   <div>
-    {{ theme.lastUpdated ?? 'Edit this page' }}:
+    {{ theme.lastUpdated ?? 'Last Updated' }}:
     <time :datatime="isoDatetime">
       {{ datetime }}
     </time>