Make PREVENT_STUCK_MODIFIERS the default (#3107)

* Remove chording as it is not documented, not used, and needs work.

* Make Leader Key an optional feature.

* Switch from `PREVENT_STUCK_MODIFIERS` to `STRICT_LAYER_RELEASE`

* Remove `#define PREVENT_STUCK_MODIFIERS` from keymaps.

keyboards/atreus62/keymaps/mneme/config.h

@@ -1,6 +1,5 @@
 #define ONESHOT_TIMEOUT 3000
 #define TAPPING_TERM 200
-#define PREVENT_STUCK_MODIFIERS
 #define FORCE_NKRO
 #define LEADER_TIMEOUT 1000
 

keyboards/atreus62/keymaps/mneme/rules.mk

@@ -3,3 +3,4 @@ NKRO_ENABLE = true
 MOUSEKEY_ENABLE = no
 EXTRAKEY_ENABLE = yes
 CONSOLE_ENABLE = no
+LEADER_ENABLE = yes