comment output file string block

Usecases/README.md

@@ -262,6 +262,7 @@ output_string = "./output/{}-{}_timesteps{}_P{}".format(
     datestr, use_case, number_of_timesteps, FEM_Lagrange_degree
     )
 ~~~
+This block influences the naming of the output directory. Unless you are unhappy with the naming scheme of output directories, you don't need to touch this block on a per usecase basis.
 
 ### DOMAIN SUBSTRUCTURING
 ~~~python
@@ -271,7 +272,7 @@ interface_def_points = substructuring.interface_def_points
 adjacent_subdomains = substructuring.adjacent_subdomains
 subdomain_def_points = substructuring.subdomain_def_points
 outer_boundary_def_points = substructuring.outer_boundary_def_points
-~~
+~~~
 
 ### MODEL CONFIGURATION
 ~~~python