While this change is not 100% required now, it's good habit
and we are checking for it since Moodle 4.4.
All the changes in this commit have been applied automatically
using the moodle.PHPUnit.TestReturnType sniff and are, exclusively
adding the ": void" return types when missing.
In PHP 8.1, any implicit conversion of float to int, which leads to a loss in precision, is now deprecated.
To avoid the error warning, the code must explicitly convert a floating value to an integer.
Andrew Nicols