Fix typo (#812)

Author: NicoHood

src/pages/docs/width.mdx

@@ -107,7 +107,7 @@ Use `w-{fraction}` or `w-full` to set an element to a percentage based width.
 
 <div class="flex ...">
   <div class="**w-1/2** ... ">w-1/2</div>
-  <div class="**w-1/2** ..."">w-1/2</div>
+  <div class="**w-1/2** ... ">w-1/2</div>
 </div>
 <div class="flex ...">
   <div class="**w-2/5** ...">w-2/5</div>