Update Bluetooth docs (#4062)

* syncing upstream

* Bluetooth Doc update

More Description in bluetooth section, Addition to Config options rules.mk section.

* merge upstream

chibios

* lib/chibios checkout

* Additional EZ key Section

added back EZ-Key diy link, Cleaned up some errors

docs/config_options.md

@@ -245,7 +245,9 @@ Use these to enable or disable building certain features. The more you have enab
 * `UNICODE_ENABLE`
   * Unicode
 * `BLUETOOTH_ENABLE`
-  * Enable Bluetooth with the Adafruit EZ-Key HID
+  * Legacy option to Enable Bluetooth with the Adafruit EZ-Key HID. See BLUETOOTH
+* `BLUETOOTH`
+  * Current options are AdafruitEzKey, AdafruitBLE, RN42
 * `SPLIT_KEYBOARD`
   * Enables split keyboard support (dual MCU like the let's split and bakingpy's boards) and includes all necessary files located at quantum/split_common
 * `WAIT_FOR_USB`