diff --git a/USAGE_EXTENSIBILITY.md b/USAGE_EXTENSIBILITY.md
index 20bd13ea..6981500f 100644
--- a/USAGE_EXTENSIBILITY.md
+++ b/USAGE_EXTENSIBILITY.md
@@ -26,11 +26,11 @@ renderer.heading = function (text, level) {
   var escapedText = text.toLowerCase().replace(/[^\w]+/g, '-');
 
   return `<h${level}>
-  			<a name="'${escapedText}'" class="anchor" href="#${escapedText}">
-  				<span class="header-link"></span>
-  			</a>
-  			${text}
-		</h${level}>`;
+            <a name="'${escapedText}'" class="anchor" href="#${escapedText}">
+              <span class="header-link"></span>
+            </a>
+            ${text}
+          </h${level}>`;
 };
 
 // Run marked