Also added a source code link.

Note, the docstrings (for the most part) were already very thorough
and included type information.

Removed function type annotations from _pyio.py.

one reference to a huge object even when an exception is raised.

These are reserved for third-party use.

by Ross Lagerwall.

Issue 10889: Support slicing and indexing of large ranges (no docs changes, since, as far as I know, we never said anywhere that this *didn't* work)

can be cut and pasted are more important than having a doctests
on examples that already work.

Based on part of A. Belopolsky's patch.

initial data is provided in an array object with correct type.

Issue 10556: test_zipimport_support implicitly imports too many modules (including _ssl) to safely clobber sys.modules after each test