fix: Support sort lesson by weight

Signed-off-by: TheYoungManLi <cjl@kubesphere.io>

content/zh/learn/level_1/_index.md

@@ -1,5 +1,6 @@
 ---
 linkTitle: 第一章：容器化基础
+weight: 1
 
 _build:
     render: false

content/zh/learn/level_2/_index.md

@@ -1,5 +1,6 @@
 ---
 linkTitle: 第二章：Kubernetes 基础
+weight: 2
 
 _build:
     render: false

layouts/learn/list.html

@@ -77,7 +77,7 @@
     <div class="common-layout">
         <h2>{{ .Params.section6.title }}</h2>
         <ul class="level">
-            {{ range .Page.Sections }}
+            {{ range sort .Page.Sections "Weight" }}
             <li>
                 <p class="title">{{ .LinkTitle }}</p>
                 <table>