Feature or enhancement

Follow-up of gh-86726.

The tkinter reference section was thoroughly overhauled and now documents the full public API accurately (gh-86726 and the fixes in #153549). The narrative sections that precede it — "Tkinter life preserver" and "Handy reference" in Doc/library/tkinter.rst — were not part of that pass and still read like a late-1990s tutorial. This issue tracks bringing them up to the same standard.

They are not factually wrong, so this is editorial, not a bug fix. The base-widget teaching examples should stay where they illustrate core concepts; the goal is to refresh tone, drop dated references, and cross-link to the now-complete reference.

Concrete items:

• Classic non-themed examples (e.g. Button(self, fg="red", bg="blue"), the packer and window-manager walkthroughs) give no pointer to the ttk widgets the introduction recommends. Add cross-references or themed equivalents.
• Remove the page-number citations to Ousterhout's Tcl and the Tk Toolkit ("page 160", "page 183", "page 201") — they refer to one print edition.
• Review the dated external links (the Shipman Tkinter 8.5 reference and the SourceForge "Converting to Tile widgets" monograph).
• Reconcile the informal "Tk option data types" and "Packer options" lists with the now-comprehensive reference — deduplicate and cross-link.
• Give "Bindings and events" and "The index parameter" a consistency pass to match the reference.

Out of scope: no API changes.

Linked PRs

• gh-153550: Remove out-of-date page-number citations from tkinter docs #153642
• gh-153550: Modernize the older prose sections of the tkinter documentation #153647
• [3.15] gh-153550: Modernize the older prose sections of the tkinter documentation (GH-153647) #153773
• [3.14] gh-153550: Modernize the older prose sections of the tkinter documentation (GH-153647) #153774
• [3.13] gh-153550: Modernize the older prose sections of the tkinter documentation (GH-153647) #153775