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/handwired/MS_sculpt_mobile/config.h

@@ -28,10 +28,10 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #define DESCRIPTION     6000
 
 /* key matrix size */
-#define MATRIX_ROWS 8 
-#define MATRIX_COLS 18 
+#define MATRIX_ROWS 8
+#define MATRIX_COLS 18
 
-#ifdef ASTAR 
+#ifdef ASTAR
 #define PRODUCT         sculpt mobile astar
                         /*0   1   2   3    4   5  6   7   8 */
 #define MATRIX_ROW_PINS {D7, C6, D4, D0, D1, D3, D2, E2}
@@ -95,6 +95,4 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 //#define NO_ACTION_MACRO
 //#define NO_ACTION_FUNCTION
 
-#define PREVENT_STUCK_MODIFIERS
-
 #endif