gh-137897: Deprecate the -R option

[StanFromIreland]

I have also removed the duplicated docs, which can be found under the __hash__ doc.

cpython/Doc/reference/datamodel.rst

Lines 2220 to 2236 in 0c8fecc

	.. note::
	By default, the :meth:`__hash__` values of str and bytes objects are
	"salted" with an unpredictable random value. Although they
	remain constant within an individual Python process, they are not
	predictable between repeated invocations of Python.
	This is intended to provide protection against a denial-of-service caused
	by carefully chosen inputs that exploit the worst case performance of a
	dict insertion, *O*\ (*n*\ :sup:`2`) complexity. See
	http://ocert.org/advisories/ocert-2011-003.html for details.
	Changing hash values affects the iteration order of sets.
	Python has never made guarantees about this ordering
	(and it typically varies between 32-bit and 64-bit builds).
	See also :envvar:`PYTHONHASHSEED`.

• Issue: Deprecate the -R option #137897

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