moved to newer version of clang

[pjljvandelaar]

Fixes applied:

• Removed clang as dependency - keeping only libclang-ng==22.1.4.2 as it also includes the language bindings.
• Fixed clang_ast_node.py — File objects are no longer hashable in newer bindings; changed _collect_expansions to use child.extent.start.file.name (string) instead of the raw File object.
• Added _CRT_USE_BUILTIN_OFFSETOF to the existing SYSTEM_MACROS allowlist (newer clang surfaces this predefined macro as an AST child; the file already had this exact filtering mechanism for other builtins).
• Updated 8 expected strings in test_c_pattern_factory.py — newer clang now populates Cursor.spelling for binary operators (e.g. <=, ==) where it used to return ""; this is an intentional upstream improvement (there was already a TODO comment anticipating it), so the test expectations needed updating, not the source.