Change heading level for Cmder section in terminals.md

Author: lazka

web/docs/terminals.md

@@ -109,7 +109,7 @@ C:\\msys64\\msys2_shell.cmd -defterm -here -no-start -ucrt64
 
 * Now close and restart Konsole.
 
-### Cmder
+## Cmder
 
 ![image](cmder.png){: align=right width=45% }