This reverts commit 886483e2b9bbabf60ab769683269b873381dd5ee.

* Add %T format to PyUnicode_FromFormatV(), and so to
  PyUnicode_FromFormat() and PyErr_Format(), to format an object type
  name: equivalent to "%s" with Py_TYPE(obj)->tp_name.
* Replace Py_TYPE(obj)->tp_name with %T format in unicodeobject.c.
* Add unit test on %T format.
* Rename unicode_fromformat_write_cstr() to
  unicode_fromformat_write_utf8(), to make the intent more explicit.

Py_DecodeLocale() and Py_EncodeLocale() now use the UTF-8 encoding on
Windows if Py_LegacyWindowsFSEncodingFlag is zero.

pymain_read_conf() now sets Py_LegacyWindowsFSEncodingFlag in its
loop, but restore its value at exit.

Also, update the list of exceptions that may raised by PyMarshal_*
functions. We usually don't document exceptions raised by a
function, but in this case most of them were already documented
in C API and standard library documentation.

The existing doc had a number of info gaps and was a little hard to use.  This patch provides several quick-reference tables as well as examples.