[12.x] Fix PHPDoc for Arr::sole method

[AhmedAlaa4611]

Description

This PR corrects the PHPDoc comment for the Illuminate\Support\Arr::sole method.

• Updates the word collection to array, which better reflects the actual data type the method operates on.
• Updates the @param tag for the $callback argument to callable|null to match the method signature.

These changes improve code clarity and align the documentation with the method's actual behavior.

[shaedrich]

If you wanted, you could significantly shorten the method body as well

    public static function sole($array, ?callable $callback = null)
    {
        if ($callback) {
            $array = static::where($array, $callback);
        }

-		$count = count($array);
-
-       if ($count === 0) {
-           throw new ItemNotFoundException;
-       }
-
-       if ($count > 1) {
-           throw new MultipleItemsFoundException($count);
-       }
-
-       return static::first($array);
+       return match ($count = count($array)) {
+       	0 => new ItemNotFoundException,
+			1 => static::first($array),
+			default => new MultipleItemsFoundException($count),
+       };
	}

but that would probably be a bit out of scope