Do a hard kill for failed homing moves (#11161)

Marlin/src/module/endstops.h

@@ -144,6 +144,9 @@ class Endstops {
     // Disable / Enable endstops based on ENSTOPS_ONLY_FOR_HOMING and global enable
     static void not_homing();
 
+    // If the last move failed to trigger an endstop, call kill
+    static void validate_homing_move();
+
     // Clear endstops (i.e., they were hit intentionally) to suppress the report
     FORCE_INLINE static void hit_on_purpose() { hit_state = 0; }