[Keymap] snowkuma Planck keymap (#6225)

* Snowkuma's planck layout.

Heavily influenced by both Planck and SDOTHUMs layouts.  I have tried to
implement a comfortable layout with a wide stagger and a minimal set of
key usage.

Still a work in progress, hope it is useful to others.

* Adds simple readme file and images of layout

* Removes unused experimental definitions

* Update readme.md

Adds images of layout to readme.

* Removes accidentally added test keymap .swn .swo .swp files

* Updates config.h replaces include guard

As suggested by @noroadsleft replaces the include guard (ifndef, define
and endif) with just `#pragma once`.

* Replaces two extra KC with inbuilt QMK equivalents

custom_keycodes.h
Replaces `___f___` with the equivalent QMK alias `_______` KC_TRNS
`___x___` with the equivalent QMK alias `XXXXXXX` KC_NO

Updates keymap.c to reflect the changes made.

* Changes keymap.c to include QMK_KEYBOARD_H

Replaces planck.h and action_layer.h includes with the single inclusion
of QMK_KEYBOARD_H which includes action_layer.h automatically.

* Update keyboards/planck/keymaps/snowkuma/keymap.c

Co-Authored-By: noroadsleft <18669334+noroadsleft@users.noreply.github.com>

* Update keymap.c

removes unused Coleman key code from enum planck_keycodes

* Update keymap.c removes COLEMAK key code logic

1 files changed, 60 insertions, 0 deletions

diff --git a/keyboards/planck/keymaps/snowkuma/custom_keycodes.h b/keyboards/planck/keymaps/snowkuma/custom_keycodes.h
new file mode 100644
index 000000000..5e4353c04
--- /dev/null
+++ b/keyboards/planck/keymaps/snowkuma/custom_keycodes.h
@@ -0,0 +1,60 @@
+// These definitions are for convenience.
+// It is not wise to put sensitive information here such as passwords
+// as anyone with access to your keyboard will be able to use them!
+
+// magnet keycodes
+#define M_LEFT LCA(KC_LEFT)
+#define M_TOP LCA(KC_UP)
+#define M_BOTT LCA(KC_DOWN)
+#define M_RGHT LCA(KC_RGHT)
+
+#define M_TOPL LCA(KC_U)
+#define M_TOPR LCA(KC_I)
+#define M_BOTL LCA(KC_J)
+#define M_BOTR LCA(KC_K)
+
+#define M_L13 LCA(KC_D)
+#define M_L23 LCA(KC_E)
+#define M_C13 LCA(KC_F)
+#define M_R23 LCA(KC_T)
+#define M_R13 LCA(KC_G)
+
+#define M_NEXT LCAG(KC_RGHT)
+#define M_PREV LCAG(KC_LEFT)
+
+#define M_MAX LCA(KC_ENT)
+#define M_CEN LCA(KC_C)
+#define M_REST LCA(KC_BSPC)
+
+// Shortcuts
+#define INPUT_L LCAG(KC_SPC)
+#define TXT_PLS LGUI(KC_PLUS)
+#define TXT_MIN LGUI(KC_MINS)
+#define SC_CAPF LGUI(LSFT(KC_3))  // Capture the full screen to file
+#define SC_CAPP LGUI(LSFT(KC_4))  // Capture portion of screen to file
+ 
+// Special Layer keycodes
+#define ESC_NUM LT(_NUMBER, KC_ESC)
+#define BSP_REG LT(_REGEX, KC_BSPC)
+#define DEL_REG LT(_REGEX, KC_DEL)
+#define MIN_ARR LT(_ARRANGE, KC_MINS)
+#define TAB_SFT LSFT_T(KC_TAB)
+#define SPC_SYM LT(_SYMBOL, KC_SPC)
+#define ENT_THU LT(_THUMB, KC_ENT)
+#define FUN_L MO(_FUNCTION)
+
+// HOMEROW SHIFT
+#define T_SFT LSFT_T(KC_T)
+#define N_SFT RSFT_T(KC_N)
+
+// Special Characters
+#define GBP LALT(KC_3)
+#define EURO LALT(S(KC_2))
+
+// Modifier tap holds
+#define Q_CTL LCTL_T(KC_Q)
+#define W_ALT LALT_T(KC_W)
+#define F_GUI LGUI_T(KC_F)
+#define U_GUI LGUI_T(KC_U)
+#define Y_ALT LALT_T(KC_Y)
+#define SCL_CTL LCTL_T(KC_SCLN)