feat($core): do not register global components at themePath/components (close: #877)

Author: ulivz

packages/@vuepress/core/lib/prepare/AppContext.js

@@ -123,8 +123,7 @@ module.exports = class AppContext {
       .use('@vuepress/last-updated', shouldUseLastUpdated)
       .use('@vuepress/register-components', {
         componentsDir: [
-          path.resolve(this.sourceDir, '.vuepress/components'),
-          path.resolve(this.themePath, 'components')
+          path.resolve(this.sourceDir, '.vuepress/components')
         ]
       })
       .apply()