Add structured version info for tkinter

Feature or enhancement

The version of the Tcl and Tk libraries used for building _tkinter is only available as _tkinter.TCL_VERSION/TK_VERSION (strings with only major and minor, like '8.6') and tkinter.TclVersion/TkVersion (the same as floats). The full patch level is not exposed, although the module uses it (TCL_PATCH_LEVEL), and there is no structured form. The runtime version is available as Misc.info_patchlevel(), which needs a Tcl interpreter.

Add _tkinter.TCL_PATCH_LEVEL and _tkinter.TK_PATCH_LEVEL for the full build-time version strings, and tkinter.TCL_VERSION_INFO and tkinter.TK_VERSION_INFO, named tuples of the same type as returned by info_patchlevel(), with fields major, minor, micro, releaselevel and serial.

Linked PRs

• gh-157516

Überprüfe die bestehenden _tkinter.TCL_VERSION/TK_VERSION- und tkinter.TclVersion/TkVersion-APIs und vergleiche anschließend tkinter.Misc.info_patchlevel() hinsichtlich der Tupelform. Als abgeschlossen gilt, wenn die beiden Patchlevel-Konstanten und zwei benannte Tupel mit den Feldern major, minor, micro, releaselevel und serial bereitgestellt werden; gh-157516 ist bereits verknüpft.