feat: add rules for trailing commas in function declarations

[simPod]

Removes trailing commas on single line declarations

- function foo(int $x,): void
+ function foo(int $x): void
{
}

---

Requires comma in multiline declarations

function foo(
    $bar,
    $baz,
)

so extending args produces nice diff (one line modified)

function foo(
    $bar,
    $baz,
+   $bam,
)

[ostrolucky]

Hopefully trailing commas in function calls are incoming too? :)