update readme.md

README.md

@@ -60,6 +60,7 @@ You then get the choice to select `original dos` graphics, sounds, and music whe
  - X = zoom-out 
  - Hold ZL = speed up analog joystick mouse 
  - Hold ZR = slow down analog joystick mouse, useful to precisely position the pointer
+ - Minus = switch button mappings between two presets: ZL/ZR = slow/fast mouse and Y/X = zoom, or ZL/ZR = zoom and Y/X = slow/fast mouse
  - Double click A / double click right trigger over a text field = bring up on-screen keyboard
  - The touch screen is used for indirect mouse input, like on a laptop touchpad. Move a single finger to move the mouse pointer. Use short tap for left click. Hold a single finger while tapping a second finger for right click. Drag with two fingers to drag and drop.
 
@@ -122,6 +123,7 @@ openttd_switch.zip can be found in __cmake/__
 - compile with lzma and lzo2 compression libraries to allow loading old compressed savegames/scenarios
 - hold ZR / ZL for slow / fast mouse to make it easier to position the pointer with the left stick
 - correctly display free disk space in load/save dialogs
+- press minus to switch button mappings between two presets: ZL/ZR = slow/fast mouse, Y/X = zoom, or ZL/ZR = zoom, Y/X = slow/fast mouse
 
 1.01