Amend docs re #220

Author: MikeMcl

docs/index.html

@@ -57,7 +57,8 @@
 
     <a class='nav-title' href="#">API</a>
     <select id="version" name="version" onchange="location.href=this.value;this.selectedIndex=0">
-      <option value="" selected>v6.2.x</option>
+      <option value="" selected>v7.0.0</option>
+      <option value="legacy/v6.2.x.html">v6.2.x</option>
       <option value="legacy/v6.1.x.html">v6.1.x</option>
       <option value="legacy/v6.0.x.html">v6.0.x</option>
       <option value="legacy/v5.2.x.html">v5.2.x</option>
@@ -196,10 +197,9 @@ <h5 id="big">
     <p>Throws if <code>n</code> is invalid.</p>
     <p>
       Using <code>new</code> with Big is optional, but note that if no argument
-      is passed when doing so, or if the argument is <code>undefined</code>,
-      then a new Big constructor will be returned rather than a new Big number.
-      See <a href='#multiple'>creating additional Big number constructors</a>
-      below.
+      is passed when doing so, a new Big constructor will be returned rather
+      than a new Big number. See <a href='#multiple'>creating additional Big
+      number constructors</a> below.
     </p>
     <pre>
 x = new Big(9)                       // '9'