Changed all occurrences of indexes to indices

The words "indexes" and "indices" were both used in the docs. This just
makes it more consistent.

docs/lists.html

@@ -86,7 +86,7 @@
 			</code></pre>
 			
 			<h4 class="section-h4">Accessing elements</h4>
-			<p>You can access an element from a list by calling the subscript operator [] on it with the index of the element you want. Like most languages, indexes start at zero:
+			<p>You can access an element from a list by calling the subscript operator [] on it with the index of the element you want. Like most languages, indices start at zero:
 			</p>
 			<pre><code class="swift">
 	var names = ["Mark", "Andrew", "Paul", "Ross", "Frank", "Max"];

docs/loops.html

@@ -107,7 +107,7 @@
 			</code></pre>
 			
 			<h4 class="section-h4">For loop</h4>
-			<p>You can access an element from a list by calling the subscript operator [] on it with the index of the element you want. Like most languages, indexes start at zero:</p>
+			<p>You can access an element from a list by calling the subscript operator [] on it with the index of the element you want. Like most languages, indices start at zero:</p>
 			<pre><code class="swift">
 	var count = 0;
 	for (var i in 0...40) {