Fix typo in docstring.

Author: AmbientLighter

src/onelogin/saml2/authn_request.py

@@ -27,7 +27,7 @@ def __init__(self, settings, force_authn=False, is_passive=False, set_nameid_pol
         Constructs the AuthnRequest object.
 
         :param settings: OSetting data
-        :type return_to: OneLogin_Saml2_Settings
+        :type settings: OneLogin_Saml2_Settings
 
         :param force_authn: Optional argument. When true the AuthNRequest will set the ForceAuthn='true'.
         :type force_authn: bool