PY-25689 image Sphinx directive doesn't work in docstring documentation

[Eitol]

Fix the problem: the prefix "file: //" was not added to local image references.

ref: https://youtrack.jetbrains.com/issue/PY-25689

contributor license agreement -> ready

[Eitol]

hi @ignatov Is there any way to move this forward?

[ignatov]

@denofevil and @JB-Dmitry, please look on this.