fix link

Author: hexaeder

docs/src/data_structure.md

@@ -64,4 +64,4 @@ nothing #hide
     ```
 
 ## Extracting a `Network`-object from Containers
-`NetworkDynamics.jl` provides a [`extract_nw`](@ref) function, to get a reference to the wrapped `Network` object from different containers, such as solution objects or [integrator objects](@extref DiffEq.integrator). 
+`NetworkDynamics.jl` provides a [`extract_nw`](@ref) function, to get a reference to the wrapped `Network` object from different containers, such as solution objects or [integrator objects](https://docs.sciml.ai/DiffEqDocs/stable/basics/integrator).