Add a missing trailing dot

Author: javiereguiluz

testing/dom_crawler.rst

@@ -26,7 +26,7 @@ Many other methods are also available:
 ``filterXpath('h1')``
     Selects nodes matching the given `XPath expression`_.
 ``eq(1)``
-    Selects the node at the given index (``0`` is the first node)
+    Selects the node at the given index (``0`` is the first node).
 ``first()``
     Selects the first node (equivalent to ``eq(0)``).
 ``last()``