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/preonic/keymaps/bucktooth/config.h

@@ -4,6 +4,5 @@
 #include "../../config.h"
 
 #define FORCE_NKRO 1
-#define PREVENT_STUCK_MODIFIERS
 
 #endif

keyboards/preonic/keymaps/jacwib/config.h

@@ -4,6 +4,5 @@
 #include "../../config.h"
 
 #define FORCE_NKRO 1
-#define PREVENT_STUCK_MODIFIERS
 
 #endif

keyboards/preonic/keymaps/kuatsure/rules.mk

@@ -1 +1,2 @@
 BACKLIGHT_ENABLE  = no
+LEADER_ENABLE = yes

keyboards/preonic/keymaps/that_canadian/config.h

@@ -1,8 +0,0 @@
-#ifndef CONFIG_USER_H
-#define CONFIG_USER_H
-
-#include "../../config.h"
-
-#define PREVENT_STUCK_MODIFIERS
-
-#endif

keyboards/preonic/keymaps/zach/config.h

@@ -87,7 +87,6 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 //#define NO_ACTION_ONESHOT
 #define NO_ACTION_MACRO
 #define NO_ACTION_FUNCTION
-#define PREVENT_STUCK_MODIFIERS
 //#define DYNAMIC_MACRO_ENABLE    // Enable if you need to use the macro functionality
 //#define SPACE_CADET             // Parenthesis on L/R shift
 

keyboards/preonic/rev3/config.h

@@ -50,9 +50,6 @@
 /* Debounce reduces chatter (unintended double-presses) - set 0 if debouncing is not needed */
 #define DEBOUNCE 6
 
-/* Prevent modifiers from being stuck on after layer changes. */
-#define PREVENT_STUCK_MODIFIERS
-
 /* Mechanical locking support. Use KC_LCAP, KC_LNUM or KC_LSCR instead in keymap */
 //#define LOCKING_SUPPORT_ENABLE
 /* Locking resynchronize hack */