eliminate clang-tidy memory leak bitchery

src/demo/fission.c

@@ -33,7 +33,11 @@ drop_bricks(struct notcurses* nc, struct ncplane** arr, int arrcount){
  }
  }
  do{
- DEMO_RENDER(nc);
+ int e = demo_render(nc);
+ if(e){
+ free(speeds);
+ return e;
+ }
  // don't allow gaps in the active range. so long as felloff is true, we've only handled
  // planes which have fallen off the screen, and can be collected.
  bool felloff = true;