change repository and modify C#

docs.it4i/software/csc.md → docs.it4i/software/lang/csc.md

 # CSharp
 
-C# is available on the cluster. Activate C# by loading the Mono module:
+C# is available on the cluster.
+
+```console
+$ ml av mono
+
+-------------------- /apps/modules/lang ---------------
+   Mono/5.0.0.100
+```
+
+!!! note
+    Use the command `ml av mono` to get up-to-date versions of the modules.
+
+Activate C# by loading the Mono module:
 
 ```console
 $ ml Mono

mkdocs.yml

@@ -137,8 +137,8 @@ pages:
       - PETSc: software/numerical-libraries/petsc.md
       - Trilinos: software/numerical-libraries/trilinos.md
     - 'Languages':
-      - Java: software/java.md
-      - C#: software/csc.md
+      - Java: software/lang/java.md
+      - C#: software/lang/csc.md
       - Conda: software/lang/conda.md
       - Python: software/lang/python.md
     - 'Phys':