Tkinter: emit deprecation warning for trace_variable() etc #120220

The Variable methods trace_variable(), trace_vdelete() and trace_vinfo() wrap deprecated Tcl commands which were deleted in Tcl 9.0. Modern replacements trace_add(), trace_remove(), and trace_info() were added in Python 3.6 (#66313). They wrap Tcl commands supported since Tcl 8.4 or older, i.e. in all supported Tcl versions.

It is a time to add runtime warnings for the old methods.

Linked PRs

• gh-120220: Deprecate legacy methods for tracing variables in Tkinter #120223