Can we make sleep accept int|float? Made a PR: https://github.com/php/php-src/pull/13401
For years when I wanted to sleep for 0.1 seconds, it annoyed me that I couldn't do `sleep(0.1);` instead I had to do `usleep(figure out how many microseconds there are in 0.1 seconds and put it here);` FWIW Python's `time.sleep` also works like this: https://docs.python.org/3/library/time.html#time.sleep
