feat: add markdown-it-cjk-friendly

closes #3762
closes #4752

BREAKING CHANGE: [markdown-it-cjk-friendly](https://www.npmjs.com/package/markdown-it-cjk-friendly) is enabled by default. This intentionally deviates from the official commonmark spec for the benefit of CJK users. **For most users, no change is required.** If you were using hacks to patch `scanDelims`, you can remove those. To disable the plugin, set `markdown: { cjkFriendly: false }` in your vitepress config.

Author: brc-dd

package.json

@@ -158,6 +158,7 @@
     "markdown-it-anchor": "^9.2.0",
     "markdown-it-async": "^2.2.0",
     "markdown-it-attrs": "^4.3.1",
+    "markdown-it-cjk-friendly": "^1.2.0",
     "markdown-it-container": "^4.0.0",
     "markdown-it-emoji": "^3.0.0",
     "markdown-it-mathjax3": "^4.3.2",