README.rst style fix

pos_keyboard/README.rst

@@ -1,22 +1,23 @@
-******************************
 USB keyboard in Point of Sale.
 ******************************
 Module to connect an additional usb keyboard for Point of Sale.
 ================================================================
 The processed keys:
 ----------------------------
-=========== ===================== =================
 
+=========== ===================== =================
 type        additional keyboard   basic keyboard  
-
 =========== ===================== =================
-
-numChar     0-9                   0-9
+numChar     ``0-9``               ``0-9``
+----------- --------------------- -----------------
 mode qty    ``/``                 ``q``
+----------- --------------------- -----------------
 mode disk   ``-``                 ``d``
+----------- --------------------- -----------------
 mode price  ``*``                 ``p``
-backspace   backspace             backspace
+----------- --------------------- -----------------
+backspace   ``backspace``         ``backspace``
+----------- --------------------- -----------------
 dot         ``.``                 ``.``
-
 =========== ===================== =================