Revert "Tiny RST link fix in modules documentation"

This reverts commit e0522516.

docsite/rst/modules.rst

@@ -11,7 +11,7 @@ Introduction
 
 
 Ansible ships with a number of modules (called the 'module library')
-that can be executed directly on remote hosts or through :doc:`Playbooks <playbooks>`.
+that can be executed directly on remote hosts or through :doc:`playbooks`.
 Users can also write their own modules.   These modules can control system
 resources, like services, packages, or files (anything really), or
 handle executing system commands.