clear up some messaging in docs on fluid grid system and nesting overall

docs/scaffolding.html

@@ -173,7 +173,8 @@
   <div class="row">
     <div class="span6">
       <p>With the static (non-fluid) grid system in Bootstrap, nesting is easy. To nest your content, just add a new <code>.row</code> and set of <code>.span*</code> columns within an existing <code>.span*</code> column.</p>
-      <h4>Example</h4>
+      <h3>Example</h3>
+      <p>Nested rows should include a set of columns that add up to the number of columns of it's parent. For example, two nested <code>.span3</code> columns should be placed within a <code>.span6</code>.</p>
       <div class="row show-grid">
         <div class="span6">
           Level 1 of column
@@ -187,6 +188,21 @@
           </div>
         </div>
       </div>
+      <h3>Fluid example</h3>
+      <p>Nesting with fluid grids is a bit different: the number of nested columns doesn't need to match the parent. Instead, your columns are reset at each level because each row takes up 100% of the parent column.</p>
+      <div class="row-fluid show-grid">
+        <div class="span12">
+          Fluid 12
+          <div class="row-fluid show-grid">
+            <div class="span6">
+              Fluid 6
+            </div>
+            <div class="span6">
+              Fluid 6
+            </div>
+          </div>
+        </div>
+      </div>
     </div>
     <div class="span6">
 <pre class="prettyprint linenums">

docs/templates/pages/scaffolding.mustache

@@ -97,7 +97,8 @@
   <div class="row">
     <div class="span6">
       <p>{{_i}}With the static (non-fluid) grid system in Bootstrap, nesting is easy. To nest your content, just add a new <code>.row</code> and set of <code>.span*</code> columns within an existing <code>.span*</code> column.{{/i}}</p>
-      <h4>{{_i}}Example{{/i}}</h4>
+      <h3>{{_i}}Example{{/i}}</h3>
+      <p>{{_i}}Nested rows should include a set of columns that add up to the number of columns of it's parent. For example, two nested <code>.span3</code> columns should be placed within a <code>.span6</code>.{{/i}}</p>
       <div class="row show-grid">
         <div class="span6">
           {{_i}}Level 1 of column{{/i}}
@@ -111,6 +112,21 @@
           </div>
         </div>
       </div>
+      <h3>{{_i}}Fluid example{{/i}}</h3>
+      <p>{{_i}}Nesting with fluid grids is a bit different: the number of nested columns doesn't need to match the parent. Instead, your columns are reset at each level because each row takes up 100% of the parent column.{{/i}}</p>
+      <div class="row-fluid show-grid">
+        <div class="span12">
+          {{_i}}Fluid 12{{/i}}
+          <div class="row-fluid show-grid">
+            <div class="span6">
+              {{_i}}Fluid 6{{/i}}
+            </div>
+            <div class="span6">
+              {{_i}}Fluid 6{{/i}}
+            </div>
+          </div>
+        </div>
+      </div>
     </div>
     <div class="span6">
 <pre class="prettyprint linenums">