[PHP 8.6] Partial Function Application

### Description

Support for the upcoming version 8.6 of PHP.

_(Scheduled to be released in late November 2026)_

### Use case/motivation

The [PHP RFC: Partial Function Application (v2)](https://wiki.php.net/rfc/partial_function_application_v2) introduces a native syntax to pre-fill some arguments of a function call while leaving others open for later.

The syntax uses a `?` placeholder for a single open argument (e.g., `str_replace('hello', 'hi', ?)`) and `...` for remaining variadic arguments, completely removing the need to write verbose, custom anonymous arrow functions.

Calling a function this way returns a standard `Closure` object that only expects the remaining missing arguments.

This feature drastically cleans up functional-style programming, making it highly readable when using inline callbacks or chaining operations with the pipe operator.

### Related issues

_No response_

### Are you willing to submit a pull request?

No

No files, tests, or entry points are identified in the issue. Start by reading the linked PHP RFC and inspecting how NetBeans currently handles PHP language-version features; done means PHP 8.6 partial function application syntax is supported without regressions.

Written by the indexing model from the issue text.