doc: Add a very short README for the Planck, and a NEWS entry

Fixes #460.

Signed-off-by: Gergely Nagy <algernon@keyboard.io>

NEWS.md

@@ -81,6 +81,7 @@ Kaleidoscope has been ported to the following devices:
 
 - [Atreus](doc/plugin/Hardware-Technomancy-Atreus.md), post-2016 PCB variants with an A* MCU, and the handwired with Teensy from FalbaTech are supported, PCBs prior to 2016 and the legacy teensy2 variants are not.
 - [ErgoDox](doc/plugin/Hardware-EZ-ErgoDox.md): Originally developed to support the ErgoDox EZ, but all other compatible hardware is supported, such as the original ErgoDox and anything else wired like it, like some Dactyls.
+- [Planck](doc/plugin/Hardware-OLKB-Planck.md): AVR-based Plancks, and anything else wired similarly should be supported, as long as they use a Teensy.
 
 For more information, please see the hardware plugins' documentation.
 

doc/plugin/Hardware-OLKB-Planck.md

@@ -0,0 +1,8 @@
+# Kaleidoscope-Hardware-OLKB-Planck
+
+This is a plugin for [Kaleidoscope][fw], that adds hardware support for the
+[OLKB Planck][planck]. For now, this only supports variants with a Teensy2 MCU.
+Speakers and LEDs are not supported.
+
+ [fw]: https://github.com/keyboardio/Kaleidoscope
+ [planck]: https://olkb.com/planck