Remove redefinition of _______ in documentation example (qmk#3924)

* Remove redefinition of `_______` in documentation example

* Slight rewording to include purpose of defintions

* Update include to newer macro

docs/keymap.md

@@ -89,11 +89,15 @@ There are 3 main sections of a `keymap.c` file you'll want to concern yourself w
 
 At the top of the file you'll find this:
 
-    #include "clueboard.h"
+    #include QMK_KEYBOARD_H
 
     // Helpful defines
     #define GRAVE_MODS  (MOD_BIT(KC_LSHIFT)|MOD_BIT(KC_RSHIFT)|MOD_BIT(KC_LGUI)|MOD_BIT(KC_RGUI)|MOD_BIT(KC_LALT)|MOD_BIT(KC_RALT))
-    #define _______ KC_TRNS
+
+    /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+     *  You can use _______ in place for KC_TRNS (transparent)   *
+     *  Or you can use XXXXXXX for KC_NO (NOOP)                  *
+     * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 
     // Each layer gets a name for readability.
     // The underscores don't mean anything - you can
@@ -105,7 +109,9 @@ At the top of the file you'll find this:
     #define _FL 1
     #define _CL 2
 
-These are some handy definitions we can use when building our keymap and our custom function. The `GRAVE_MODS` definition will be used later in our custom function. The `_______` define makes it easier to see what keys a layer is overriding, while the `_BL`, `_FL`, and `_CL` defines make it easier to refer to each of our layers.
+These are some handy definitions we can use when building our keymap and our custom function. The `GRAVE_MODS` definition will be used later in our custom function, and the following `_BL`, `_FL`, and `_CL` defines make it easier to refer to each of our layers.
+
+Note: You may also find some older keymap files may also have a define(s) for `_______` and/or `XXXXXXX`. These can be used in place for `KC_TRNS` and `KC_NO` respectively, making it easier to see what keys a layer is overriding. These definitions are now unecessary, as they are included by default.
 
 ### Layers and Keymaps