[index][new_model] more descriptive text

slides/index.md

@@ -24,7 +24,7 @@ subtitle: Overview
 
 * [Property System](./properties.html)
 * [Constitutive models (material)](./materialsystem.html)
-* [New DuMu^x^ model equations](./model.html)
+* [Implementing a new model in DuMu^x^](./model.html)
 * [New Dune module](./dunemodule.html)
 
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