Fix missing file extension in Exporting projects

tutorials/export/exporting_projects.rst

@@ -174,7 +174,7 @@ the command:
 
 .. code-block:: shell
 
-    godot --path /path/to/project --export "Windows Desktop" some_name
+    godot --path /path/to/project --export "Windows Desktop" some_name.exe
 
 .. seealso::