Make the debug logging functions consistent

They now all output the same format of:
[time since program start] msg

kitty/data-types.h

@@ -426,7 +426,6 @@ void play_canberra_sound(const char *which_sound, const char *event_id, bool is_
 SPRITE_MAP_HANDLE alloc_sprite_map(unsigned int, unsigned int);
 SPRITE_MAP_HANDLE free_sprite_map(SPRITE_MAP_HANDLE);
 const char* get_hyperlink_for_id(const HYPERLINK_POOL_HANDLE, hyperlink_id_type id, bool only_url);
-void log_event(const char *format, ...) __attribute__((format(printf, 1, 2)));
 
 #define memset_array(array, val, count) if ((count) > 0) { \
     (array)[0] = (val); \