Forced named parameters

Hi everyone,

Looking [RFC] Clone with v2, especially Larry's message
(https://externals.io/message/127353#127399) I'm thinking that it might
be a good idea to allow forcing function calls to use named arguments.

Python has it by defining arguments after the variadic argument:
https://peps.python.org/pep-3102/

def compare(a, b, *v, key=None):
...

Since PHP named args work similarly, borrowing syntax makes sense. It
would look like

function f(Type $pos1, Type $pos2, ...$v, Type $named1, Type $named2)

or without the variadic

function f(Type $pos1, Type $pos2, ..., Type $named1, Type $named2)

The scope is highly configurable functions and options objects:

 function json_encode(
     mixed $value,
     ...,
     int $depth = 512,
// arguments instead of constants
// easier for the code completion
// and call strictness
     bool $hexTag = false,
// arguments can be grouped by meaning
     // and new ones can be inserted into the middle
// without breaking compatibility
bool $hexAmp = false,
     // options can have values
     string $indent = '    ',
     // ...
 ): string {
     // ...
 }

P.S. I'm just planting an idea for now, unlikely that I'm able to develop it