fix: fix spelling errors

Author: anlyyao

src/pull-down-refresh/__test__/__snapshots__/demo.test.js.snap

@@ -25,7 +25,7 @@ exports[`PullDownRefresh PullDownRefresh base demo works fine 1`] = `
         title="PullDownRefresh 下拉刷新"
       />
       <wx-view
-        class="pulldown-reflesh__content"
+        class="pulldown-refresh__content"
       >
         <t-skeleton
           loading="{{true}}"

src/pull-down-refresh/_example/base/index.wxml

@@ -12,7 +12,7 @@
       desc="用于快速刷新页面信息，刷新可以是整页刷新也可以是页面的局部刷新。"
       notice="渲染框架支持情况：WebView"
     />
-    <view class="pulldown-reflesh__content">
+    <view class="pulldown-refresh__content">
       <t-skeleton rowCol="{{rowCol1}}" loading></t-skeleton>
       <view class="row">
         <t-skeleton rowCol="{{rowCol2}}" loading></t-skeleton>

src/pull-down-refresh/_example/base/index.wxss

@@ -18,7 +18,7 @@
   line-height: 44rpx;
 }
 
-.pulldown-reflesh__content {
+.pulldown-refresh__content {
   margin: 64rpx 32rpx 0;
   position: relative;
 }