* The array "subject" of a function gets called $array.
* Further parameters should be self-descriptive if used
as a named parameter, and a full word, not an abbreviation.
* If there is a "bunch more arrays" variadic, it gets
called $arrays (because that's what was already there).
* A few functions have a variadic "a bunch more arrays,
and then a callable", and were already called $rest.
I left those as is and died a little inside.
* Any callable provided to an array function that acts
on the array is called $callback. (Nearly all were already,
I just fixed the one or two outliers.)
* array_multisort() is beyond help so I ran screaming.
PHP requires integer typehints to be written "int" and does not
allow "integer" as an alias. This changes type error messages to
match the actual type name and avoids confusing messages like
"must be of the type integer, integer given".
