fix(post-asset): strip extensions better on permalink (#5153)

* compatible with hexo-abbrlink

* strip extensions better on permalink

Author: syunaht

lib/models/post_asset.js

@@ -1,7 +1,7 @@
 'use strict';
 
 const { Schema } = require('warehouse').default;
-const { join } = require('path');
+const { join, dirname } = require('path');
 
 module.exports = ctx => {
   const PostAsset = new Schema({
@@ -19,8 +19,8 @@ module.exports = ctx => {
 
     // PostAsset.path is file path relative to `public_dir`
     // no need to urlescape, #1562
-    // strip /\.html?$/ extensions on permalink, #2134
-    return join(post.path.replace(/\.html?$/, ''), this.slug);
+    // strip extensions better on permalink, #2134
+    return join(dirname(post.path), post.slug, this.slug);
   });
 
   PostAsset.virtual('source').get(function() {