adjust mpadded length reference in chapter 2

src/fundamentals.html

@@ -407,14 +407,14 @@ <h5 id="fund_units">Length Valued Attributes</h5>
 	</tbody>
       </table>
 
-    <p>In addition, the attributes on <a href="#presm_mpadded">mpadded</a>
-     allow three <dfn>pseudo-units</dfn>, <code>height</code>,
+
+    <p>In MathML&#160;3, the attributes on <a href="#presm_mpadded">mpadded</a>
+     allowed three <dfn>pseudo-units</dfn>, <code>height</code>,
       <code>depth</code>, and <code>width</code> (taking the place of one of the usual CSS units)
       denoting the original dimensions of the content.
-    </p>
-    <p>MathML&#160;3 also allowed a deprecated usage with lengths specified as
-     a number without a unit. This  was interpreted as a multiple of the
-     reference value. This form is considered invalid in MathML&#160;4.
+      It also allowed a deprecated usage with lengths specified as
+     a number without a unit which was interpreted as a multiple of the
+     reference value. These forms are considered invalid in MathML&#160;4.
     </p>
 
     <section>