Update canoe:dhertz to use new post-init functions (#9257)

* Update to use new post-init functions

* Update readme so I don't forget reset key again

keyboards/percent/canoe/keymaps/dhertz/keymap.c

@@ -44,7 +44,7 @@ const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
       ),
 };
 
-void matrix_init_keymap(void) {
+void keyboard_post_init_user(void) {
     rgblight_enable_noeeprom();
     rgblight_sethsv_teal();
 }

keyboards/percent/canoe/readme.md

@@ -14,4 +14,6 @@ Flashing example for this keyboard ([after setting up the bootloadHID flashing e
 
     make percent/canoe:default:flash
 
+Reset Key: Hold down the key located at K11, commonly programmed as Q while plugging in the keyboard.
+
 See the [build environment setup](https://docs.qmk.fm/#/getting_started_build_tools) and the [make instructions](https://docs.qmk.fm/#/getting_started_make_guide) for more information. Brand new to QMK? Start with our [Complete Newbs Guide](https://docs.qmk.fm/#/newbs).