docs(advance): [theme] add desc for extending DefaultTheme

Author: akinoccc

.gitignore

@@ -1,5 +1,5 @@
 **/node_modules
 **/**/dist
 .idea
-packages/docs/.vitepress/cache
+./packages/docs/.vitepress/cache
 coverage

packages/docs/.vitepress/cache/deps/_metadata.json

@@ -1,40 +1,49 @@
 {
-  "hash": "82f7a7e4",
+  "hash": "54b90a79",
   "configHash": "3c7637e1",
-  "lockfileHash": "2af20ff2",
-  "browserHash": "0d392eda",
+  "lockfileHash": "122ab0a0",
+  "browserHash": "ddb6c01e",
   "optimized": {
     "vue": {
       "src": "../../../../../node_modules/.pnpm/vue@3.4.38_typescript@5.4.5/node_modules/vue/dist/vue.runtime.esm-bundler.js",
       "file": "vue.js",
-      "fileHash": "fce6372b",
+      "fileHash": "da2889df",
       "needsInterop": false
     },
     "vitepress > @vue/devtools-api": {
       "src": "../../../../../node_modules/.pnpm/@vue+devtools-api@7.0.27_vue@3.4.38_typescript@5.4.5_/node_modules/@vue/devtools-api/dist/index.js",
       "file": "vitepress___@vue_devtools-api.js",
-      "fileHash": "17624786",
+      "fileHash": "f3cb0771",
       "needsInterop": false
     },
     "vitepress > @vueuse/core": {
       "src": "../../../../../node_modules/.pnpm/@vueuse+core@10.9.0_vue@3.4.38_typescript@5.4.5_/node_modules/@vueuse/core/index.mjs",
       "file": "vitepress___@vueuse_core.js",
-      "fileHash": "aacfed4f",
+      "fileHash": "c99140c1",
       "needsInterop": false
     },
     "vue-demi": {
       "src": "../../../../../node_modules/.pnpm/vitepress@1.1.4_@algolia+client-search@4.23.3_@types+node@20.12.7_postcss@8.4.41_search-insights@2.13.0_typescript@5.4.5/node_modules/vitepress/lib/vue-demi.mjs",
       "file": "vue-demi.js",
-      "fileHash": "cb4f960e",
+      "fileHash": "74931243",
+      "needsInterop": false
+    },
+    "stylis": {
+      "src": "../../../../../node_modules/.pnpm/stylis@4.3.2/node_modules/stylis/index.js",
+      "file": "stylis.js",
+      "fileHash": "d95cdf52",
       "needsInterop": false
     }
   },
   "chunks": {
     "chunk-FIBNPOE5": {
       "file": "chunk-FIBNPOE5.js"
     },
-    "chunk-SAFGAUDD": {
-      "file": "chunk-SAFGAUDD.js"
+    "chunk-CX6MQXSB": {
+      "file": "chunk-CX6MQXSB.js"
+    },
+    "chunk-CSAU5B4Q": {
+      "file": "chunk-CSAU5B4Q.js"
     }
   }
 }