Refactor Leader key feature (#19632)

Co-authored-by: Drashna Jaelre <drashna@live.com>

users/curry/leader_user.c

@@ -0,0 +1,31 @@
+#include "curry.h"
+#include "leader_user.h"
+
+void leader_end_user(void) {
+    if (leader_sequence_one_key(KC_F)) {
+        // Select all and format
+        SEND_STRING(SS_LCTL("akf"));
+    }
+    if (leader_sequence_one_key(KC_P)) {
+        // Screenshot region
+        SEND_STRING(SS_LCTL(SS_LSFT("4")));
+    }
+    if (leader_sequence_two_keys(KC_D, KC_D)) {
+        // Copy all
+        SEND_STRING(SS_LCTL("ac"));
+    }
+}
+
+void matrix_scan_user(void) {
+    static bool has_ran_yet;
+    if (!has_ran_yet) {
+        has_ran_yet = true;
+        startup_user();
+    }
+
+#if defined(RGBLIGHT_ENABLE) || defined(RGB_MATRIX_ENABLE)
+    matrix_scan_rgb();
+#endif  // RGBLIGHT_ENABLE
+
+    matrix_scan_keymap();
+}