Unexpected "alias of" in attributes generated by autodoc.

[Abrosimov-a-a]

Describe the bug
Handmaded docstrings for attributes are ignored by sphinx autodoc and replaced by alias of.

To Reproduce

1. Create default sphinx project with autodoc extension.
2. Create example_code.py with content:

from typing import Union, Type

class MyClass:
    """Class ``MyClass`` docstring."""

    #: This comment is not displayed.
    int_attr = int
    #: This comment is not displayed.
    typed_attr: Union[Type[int], Type[str]] = int

3. Build html documenation for example_code.py.

Expected behavior
I expect to see This comment is not displayed. docstring for int_attr and typed_attr attributes,
but I see alias of int docstring.

Environment info

• OS: Linux Debian Buster
• Python version: 3.7.3
• Sphinx version: v3.2.1, v3.5.4
• Sphinx extensions: sphinx.ext.autodoc

Additional context
Possibly related:

• No way to override "alias of" text, generated by autodoc #4422
• Inconsistent behaviour with type alias documentation (not overwriting all the default messages, just some) #8061