Soft Reset via Serial or post-kill button click (#21652)

Co-authored-by: Scott Lahteine <thinkyhead@users.noreply.github.com>

Marlin/src/HAL/TEENSY35_36/HAL.cpp

@@ -86,6 +86,8 @@ uint8_t HAL_get_reset_source() {
   return 0;
 }
 
+void HAL_reboot() { _reboot_Teensyduino_(); }
+
 extern "C" {
   extern char __bss_end;
   extern char __heap_start;

Marlin/src/HAL/TEENSY35_36/HAL.h

@@ -101,7 +101,7 @@ void HAL_clear_reset_source();
 // Reset reason
 uint8_t HAL_get_reset_source();
 
-inline void HAL_reboot() {}  // reboot the board or restart the bootloader
+void HAL_reboot();
 
 FORCE_INLINE void _delay_ms(const int delay_ms) { delay(delay_ms); }