chore: add HJKL keybindings to the README

README.md

@@ -34,6 +34,7 @@ After you've installed Pixel Picker, it will live in your menu bar. You have man
 * Configure a keyboard shortcut in the dropdown menu and press that to activate the picker
 * Select the "Pick a Pixel" item in the dropdown menu to activate the picker
 * Simply right-click the menu item and the picker will activate
+* _Pro-tip:_ Use the <kbd>H</kbd>, <kbd>J</kbd>, <kbd>K</kbd> and <kbd>L</kbd> keys to move the picker pixel by pixel
 
 Once you have the picker open, it should be quite straightforward! Move your mouse around the screen and click (or press <kbd>space</kbd> on the pixel you want.
 You can also hold down the <kbd>control (⌃)</kbd> key (this can be changed to another key) while the picker is open, and the picker will enter "Focus Mode". This will zoom the pixel preview even further, and will slow down the picker's movement to make it easier to pick that hard-to-get pixel!