Add trailing newline at end of file

Author: meaghanlewis

docs/core/tools/dotnet-run.md

@@ -223,4 +223,5 @@ The environment is constructed in the same order as this list, so the `-e|--envi
 
   ```dotnetcli
   dotnet run -f net6.0 -arg1 -- arg2 arg3
-  ```
+  ```
+