docs: update

Author: kitian616

docs/_docs/en/4.2-grid.md

@@ -43,15 +43,15 @@ key: docs-grid
 
 <div class="grid-example my-5">
   <div class="grid">
-    <div class="cell cell--12 cell--lg-6  content">12/12/6 cells</div>
+    <div class="cell cell--12 cell--lg-6 content">12/12/6 cells</div>
     <div class="cell cell--12 cell--md-4 cell--lg-2 content">12/4/2 cells</div>
     <div class="cell cell--12 cell--md-8 cell--lg-4 content">12/8/4 cells</div>
   </div>
 </div>
 
 ```html
 <div class="grid">
-  <div class="cell cell--12 cell--lg-6  content">12/12/6 cells</div>
+  <div class="cell cell--12 cell--lg-6 content">12/12/6 cells</div>
   <div class="cell cell--12 cell--md-4 cell--lg-2 content">12/4/2 cells</div>
   <div class="cell cell--12 cell--md-8 cell--lg-4 content">12/8/4 cells</div>
 </div>