Update eio function return type #4124
   Merged  
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All the eio_ function return false on failure.
The description say
resourceas https://www.php.net/manual/en/function.eio-busy.php#refsect1-function.eio-busy-descriptionbut everytime it's say it can return false on failure
https://www.php.net/manual/en/function.eio-busy.php#refsect1-function.eio-busy-returnvalues
(On the phpstorm-stubs, it was documented
resource|boolbut I also updated the return type in JetBrains/phpstorm-stubs#1759)