[Phoebe] Keymap improvements (#9092)

Enable leader key with some useful macros, use fancier design for keymap previews in code, other smaller tweaks

keyboards/maxr1998/phoebe/config.h

@@ -57,6 +57,10 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #define RGBLIGHT_EFFECT_CHRISTMAS
 #define RGBLIGHT_EFFECT_CHRISTMAS_STEP 1
 
+/* Leader key setup */
+#define LEADER_PER_KEY_TIMING
+#define LEADER_TIMEOUT 250
+
 /*
  * Feature disable options
  *  These options are also useful to firmware size reduction.