Adds Zero Transaction Fee Section

To make it explicit how to disable fess following other models with a "disable" section.

03 Writing Algorithms/24 Reality Modeling/04 Transaction Fees/01 Key Concepts/02 Set Models.php

@@ -2,12 +2,14 @@
 
 
 <div class="section-example-container">
-    <pre class="csharp">// In Initialize
-var security = AddEquity("SPY");
-security.SetFeeModel(new ConstantFeeModel(0));</pre>
-    <pre class="python"># In Initialize
-security = self.add_equity("SPY")
-security.set_fee_model(ConstantFeeModel(0))</pre>
+    <pre class="csharp">public override Initialize()
+{
+    var security = AddEquity("SPY");
+    security.SetFeeModel(new ConstantFeeModel(0));
+}</pre>
+    <pre class="python">def initialize(self):
+    security = self.add_equity("SPY")
+    security.set_fee_model(ConstantFeeModel(0))</pre>
 </div>
 
 <p>You can also set the fee model in a <a href='/docs/v2/writing-algorithms/initialization#07-Set-Security-Initializer'>security initializer</a>. If your algorithm has a dynamic universe, use the security initializer technique. In order to initialize single security subscriptions with the security initializer, call <code class="csharp">SetSecurityInitializer</code><code class="python">set_security_initializer</code> before you create the subscriptions.</p>

03 Writing Algorithms/24 Reality Modeling/04 Transaction Fees/01 Key Concepts/05 Zero Transaction Fees.html

@@ -0,0 +1,12 @@
+<p>To model zero transaction fees, use the <a href='/docs/v2/writing-algorithms/reality-modeling/transaction-fees/supported-models'>ConstantFeeModel</a> with zero as <code>fee</code>.</p>
+
+<div class="section-example-container">
+    <pre class="csharp">public override Initialize()
+{
+    var security = AddEquity("SPY");
+    security.SetFeeModel(new ConstantFeeModel(fee: 0m));
+}</pre>
+    <pre class="python">def initialize(self):
+    security = self.add_equity("SPY")
+    security.set_fee_model(ConstantFeeModel(fee=0))</pre>
+</div>

03 Writing Algorithms/24 Reality Modeling/04 Transaction Fees/02 Supported Models/02 Constant Model.html

@@ -1,4 +1,4 @@
-<p>The <code>ConstantFeeModel</code> applies the absolute value of a constant fee to each order. It's the default fee model of the <a href='/docs/v2/writing-algorithms/reality-modeling/brokerages/supported-models/quantconnect-paper-trading'>DefaultBrokerageModel</a> if you trade Forex, CFD, or Crypto assets.</p>
+<p>The <code>ConstantFeeModel</code> applies the absolute value of a constant fee to each order. It's the default fee model of the <a href='/docs/v2/writing-algorithms/reality-modeling/brokerages/supported-models/quantconnect-paper-trading'>DefaultBrokerageModel</a> if you trade Forex, CFD, or Crypto assets. Use this model to set <a href='/docs/v2/writing-algorithms/reality-modeling/transaction-fees/key-concepts#05-Zero-Transaction-Fees'>zero transaction fees</a>.</p>
 
 <div class="section-example-container">
 <pre class="csharp">security.SetFeeModel(new ConstantFeeModel(0.05m));</pre>
@@ -20,13 +20,13 @@
         <tr>
             <td><code>fee</code></td>
 	        <td><code class="csharp">decimal</code><code class="python">float</code></td>
-            <td>The order fee quantity<br></td>
+            <td>The order fee quantity</td>
             <td></td>
         </tr>
         <tr>
             <td><code>currency</code></td>
 	        <td><code class="csharp">string</code><code class="python">str</code></td>
-            <td>The order fee currency<br></td>
+            <td>The order fee currency</td>
             <td>"USD"</td>
         </tr>
     </tbody>