Fix #225 typo in cart lib docs
diff --git a/user_guide/libraries/cart.html b/user_guide/libraries/cart.html
index fb5f662..ba95b24 100644
--- a/user_guide/libraries/cart.html
+++ b/user_guide/libraries/cart.html
@@ -314,7 +314,7 @@
<p>Returns TRUE (boolean) if a particular row in the cart contains options. This function is designed to be used in a loop with <dfn>$this->cart->contents()</dfn>, since you must pass the <kbd>rowid</kbd> to this function, as shown in the <dfn>Displaying the Cart</dfn> example above.</p>
-<h2>$this->cart->options(rowid);</h2>
+<h2>$this->cart->product_options(rowid);</h2>
<p>Returns an array of options for a particular product. This function is designed to be used in a loop with <dfn>$this->cart->contents()</dfn>, since you must pass the <kbd>rowid</kbd> to this function, as shown in the <dfn>Displaying the Cart</dfn> example above.</p>