Incorrect and missing statements in the xml.sax documentation

[serhiy-storchaka]

Several statements in the documentation of xml.sax do not match the behaviour, and a part of the API is not documented.

• The keyword argument of parse() and parseString() is errorHandler, not error_handler, so the documented name raises TypeError.
• The default value of the parser_list argument of make_parser() is (), not [].
• The source of parse() can also be a system identifier, which is opened as a URL if it does not refer to an existing file.
• The type of the declaration-handler property is given as xml.sax.sax2lib.DeclHandler, which does not exist, and the type of the dom-node property as the Java org.w3c.dom.Node.
• Names are interned in a dictionary, not with a built-in intern function, which Python 3 does not have.
• IncrementalParser is said to add three methods, but it adds four, and its parse() implementation uses prepareParser(), feed() and close(), not reset().
• default_parser_list, SAXReaderNotAvailable, property_encoding, property_interning_dict, IncrementalParser.prepareParser(), XMLFilterBase.getParent() and setParent() are not documented.
• It is not said that the parser based on Expat does not support the namespace-prefixes, validation and external-parameter-entities features, nor the declaration-handler, dom-node and encoding properties.
• parse(), parseString(), AttributesImpl and XMLGenerator have no docstrings.

Linked PRs

• gh-156829: Fix inaccuracies in the xml.sax documentation #156830
• [3.15] gh-156829: Fix inaccuracies in the xml.sax documentation (GH-156830) #156842
• [3.14] gh-156829: Fix inaccuracies in the xml.sax documentation (GH-156830) #156843
• [3.13] gh-156829: Fix inaccuracies in the xml.sax documentation (GH-156830) #156844