avoid incorrect syntax highlighting

also remove spaces before '::'s

docs/source/opera_cake.rst

@@ -147,13 +147,13 @@ In time mode, the A0 port connection switches automatically over time, counted i
 
 To cycle through four ports, one port every 1000 samples:
 
-.. code-block :: sh
+.. code-block:: none
 
 	hackrf_operacake -m time -t A1:1000 -t A2:1000 -t A3:1000 -t A4:1000
 
 When the duration on multiple ports is the same, the ``-w`` option can be used to set the default dwell time:
 
-.. code-block :: sh
+.. code-block:: none
 
 	hackrf_operacake --mode time -w 1000 -t A1 -t A2 -t A3 -t A4