update tmk link

readme.md

@@ -35,7 +35,7 @@ This is not a tiny project. While this is the main readme, there are many other
 * The list of possible keycodes you can use in your keymap is actually spread out in a few different places:
   * [doc/keycode.txt](doc/keycode.txt) - an explanation of those same keycodes.
   * [quantum/keymap.h](quantum/keymap.h) - this is where the QMK-specific aliases are all set up. Things like the Hyper and Meh key, the Leader key, and all of the other QMK innovations. These are also explained and documented below, but `keymap.h` is where they're actually defined.
-* The [TMK documentation](doc/TMK_readme.md). QMK is based on TMK, and this explains how it works internally.
+* The [TMK documentation](doc/TMK_README.md). QMK is based on TMK, and this explains how it works internally.
 
 # Getting started