fix typo in logical-mbp.html

Author: ppeyliang

learn/writing-modes/logical-mbp.html

@@ -56,7 +56,7 @@
       <div class="wrapper">
         <div class="box physical">
           <h2>Physical Properties</h2>
-          <p>A paragraph. Demonstrating Logical Properties in CSS.</p>
+          <p>A paragraph. Demonstrating Physical Properties in CSS.</p>
         </div>
         <div class="box logical">
           <h2>Logical Properties</h2>