fix: Use selector in favicon prop

Author: ktquez

Diff for: docs/guide/favicon.md

@@ -1,8 +1,8 @@
 # Favicon
 
-| prop        | Type      | default
-| ----------- | --------- | ---------- 
-| `favicon`   | Boolean   | `true`
+| prop        | Type                    | default               |  Description
+| ----------- | ----------------------- | --------------------- | ------------------------ 
+| `favicon`   | `String` \| `Boolean`   | `link[rel="icon"]`    | You can define the selector of the desired favicon (e.g. `#favicon`) or to disable this functionality, just by setting it to `false`.
 
 You can switch the favicon according to the `prefers-color-scheme`.
 

Diff for: src/DarkMode.vue

@@ -62,8 +62,8 @@ export default {
       default: '%cm color mode is enabled'
     },
     favicon: {
-      type: Boolean,
-      default: true
+      type: [String, Boolean],
+      default: 'link[rel="icon"]'
     }
   },
 
@@ -162,7 +162,7 @@ export default {
     toggleFavicon (mode) {
       if (!this.favicon) return
       this.$nextTick(() => {
-        const favicon = document.querySelector('link[rel="icon"]')
+        const favicon = document.querySelector(this.favicon)
         if (!favicon) return
         const href = favicon.getAttribute('href')
         const lastFour = href.substr(-4, 4)