Add structured version info for pyexpat

Feature or enhancement

pyexpat.EXPAT_VERSION (from XML_ExpatVersion()) and pyexpat.version_info (from XML_ExpatVersionInfo()) describe the Expat library loaded at runtime: both functions are compiled into libexpat from its XML_MAJOR_VERSION, XML_MINOR_VERSION and XML_MICRO_VERSION macros. The same macros evaluated in pyexpat.c give the version of the headers the module was built against, which is what the #if XML_COMBINED_VERSION >= ... checks in the module depend on. The two can differ when a system libexpat is used. The build-time version is not exposed to Python; it can only be inferred from which parser methods exist.

Add pyexpat.VERSION_INFO for the build-time version, and make pyexpat.version_info a named tuple.

Linked PRs

• gh-157474

Comienza en pyexpat.c, donde se exponen las macros de versión de Expat y las API de versión en tiempo de ejecución. Sigue las definiciones existentes de VERSION_INFO y version_info y, después, verifica que la versión de compilación se exponga por separado y que version_info tenga un comportamiento de tupla con nombre. Comprueba las pruebas de la API de pyexpat, si están disponibles, y confirma que ambas versiones se informan correctamente cuando difieren.