[docs] [issue37779] configparser: add documentation about several read() behaviour

[SilentGhost]

Change by SilentGhost <ghost.adh at runbox.com>:


----------
assignee:  -> docs at python
components: +Documentation -Cross-Build
nosy: +docs at python -Alex.Willmer

_______________________________________
Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue37779>
_______________________________________