Fix link to openPASS standard slides PDF

closes #184 (closed)

doc/source/user_guide/10_overview.rst

@@ -33,7 +33,7 @@ Let’s have a look at what that means:
   * Enables simulation of whole traffic scenarios. That includes stochastic variation of those scenarios, intervention through detection of events and triggered actions and much more.
   * To get a better understanding about how these simulations are performed, please look at the scenario-based simulation tutorial.
 
-For beginners, this presentation gives more illustrations and background about openPASS: https://openpass.eclipse.org/target_objectives/openpass_at_a_glance.pdf
+For beginners, this presentation gives more illustrations and background about openPASS: https://openpass.eclipse.org/target_objectives/openPASS_at_a_glance.pdf
 
 Getting Started
 ---------------