gh-90117: handle dict and mapping views in pprint (#30135)

* Teach pprint about dict views with PrettyPrinter._pprint_dict_view and ._pprint_dict_items_view.
* Use _private names for _dict_*_view attributes of PrettyPrinter.
* Use explicit 'items' keyword when calling _pprint_dict_view from _pprint_dict_items_view.
* 📜🤖 Added by blurb_it.
* Improve tests
* Add tests for collections.abc.[Keys|Items|Mapping|Values]View support in pprint.
* Add support for collections.abc.[Keys|Items|Mapping|Values]View in pprint.
* Split _pprint_dict_view into _pprint_abc_view, so pretty-printing normal dict views and ABC views is handled in two simple methods.
* Simplify redundant code.
* Add collections.abc views to some existing pprint tests.
* Test that views from collection.UserDict are correctly formatted by pprint.
* Handle recursive dict and ABC views.
* Test that subclasses of ABC views work in pprint.
* Test dict views coming from collections.Counter.
* Test ABC views coming from collections.ChainMap.
* Test odict views coming from collections.OrderedDict.
* Rename _pprint_abc_view to _pprint_mapping_abc_view.
* Add pprint test for mapping ABC views where ._mapping has a custom __repr__ and fix ChainMap test.
* When a mapping ABC view has a ._mapping that defines a custom __repr__, dispatch pretty-printing it by that __repr__.
* Add tests for ABC mapping views subclasses that don't replace __repr__, also handling those that delete ._mapping on instances.
* Simplify the pretty printing of ABC mapping views.
* Add a test for depth handling when pretty printing dict views.
* Fix checking whether the view type is a subclass of an items view, add a test.
* Move construction of the views __repr__ set out of _safe_repr.

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Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com>
Co-authored-by: Éric <merwok@netwok.org>
Co-authored-by: Oleg Iarygin <oleg@arhadthedev.net>
Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>
Co-authored-by: Gregory P. Smith <greg@krypto.org>