Add missing code on mypy errors

[sbrunner]

Use mypy api to get the messages details

before:

prospector/blender.py:81:13: error(mypy): List comprehension has incompatible type List[Message]; expected List[str]  [misc]
prospector/blender.py:101:12: error(mypy): Incompatible return value type (got "list[str]", expected "list[Message]")  [return-value]

after:

prospector/blender.py:81:12: misc(mypy): List comprehension has incompatible type List[Message]; expected List[str].
prospector/blender.py:101:11: return-value(mypy): Incompatible return value type (got "list[str]", expected "list[Message]").

Description

Use the json formater, use the API to get the message individually.

Related Issue

fix #716

Motivation and Context

Have a better mypy integration

How Has This Been Tested?

Run on Prospector code with some errors

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

[sbrunner]

Is dmypy usefull?

[Pierre-Sassoulas]

LGTM, the remark about the API is a nit.

[sbrunner]

@Pierre-Sassoulas can't we merge as it and restore the Pylint configuration when the astroid fix is available?

[Pierre-Sassoulas]

Sure

[sbrunner]

Thanks :-)