[Keymap] miryoku layout (#6171)

* First release

*  add "#pragma once" to config.h and related docs

* generate config.h with change from miryoku.org

users/manna-harbour_miryoku/config.h

@@ -0,0 +1,13 @@
+
+// generated from users/manna-harbour_miryoku/miryoku.org
+
+#pragma once
+
+// Prevent normal rollover on alphas from accidentally triggering mods.
+#define IGNORE_MOD_TAP_INTERRUPT
+
+// Enable rapid switch from tap to hold, disables double tap hold auto-repeat.
+#define TAPPING_FORCE_HOLD
+
+// Recommended for heavy chording.
+#define QMK_KEYS_PER_SCAN 4