pref: add style to preview (#55)

#### What type of PR is this?

/kind improvement

#### What this PR does / why we need it:

为瞬间预览增加样式

#### How to test it?

使用一些富文本标签，例如 code、heading、a 等，查看预览之后是否有对应的样式。

#### Which issue(s) this PR fixes:

Fixes #48 

#### Does this PR introduce a user-facing change?
```release-note
为瞬间预览增加样式
```

console/package.json

@@ -47,6 +47,7 @@
     "npm-run-all": "^4.1.5",
     "postcss": "^8.4.21",
     "prettier": "^2.8.4",
+    "sass": "^1.69.5",
     "tailwindcss": "^3.2.7",
     "typescript": "~4.7.4",
     "unplugin-icons": "^0.15.3",

console/src/components/MomentPreview.vue

@@ -194,7 +194,7 @@ const getExtname = (type: string) => {
       </div>
     </div>
     <div
-      class="moment-preview-html moments-overflow-hidden moments-relative moments-pt-1"
+      class="moment-preview-html markdown-body moments-overflow-hidden moments-relative moments-pt-1"
     >
       <div
         v-highlight

console/src/index.ts

@@ -1,5 +1,5 @@
 import "./styles/tailwind.css";
-import "./styles/index.css";
+import "./styles/index.scss";
 import { definePlugin } from "@halo-dev/console-shared";
 import MomentsList from "@/views/MomentsList.vue";
 import { markRaw } from "vue";