Some changes were made to the internal ``_pytest._code.source``, listed here
for the benefit of plugin authors who may be using it:

- The ``deindent`` argument to ``Source()`` has been removed, now it is always true.
- Support for zero or multiple arguments to ``Source()`` has been removed.
- Support for comparing ``Source`` with an ``str`` has been removed.
- The methods ``Source.isparseable()`` and ``Source.putaround()`` have been removed.
- The method ``Source.compile()`` and function ``_pytest._code.compile()`` have
  been removed; use plain ``compile()`` instead.
- The function ``_pytest._code.source.getsource()`` has been removed; use
  ``Source()`` directly instead.

Add changelog entry for code/source changes
Add changelog entry for code/source changes
