PR: Restore underlining errors and warnings in the Editor

[steff456]

Description of Changes

• Wrote at least one-line docstrings (for any new functions)
• Added unit test(s) covering the changes (if testable)

• Included a screenshot or animation (if affecting the UI, see Licecap)

Restore underlining errors and warning in the editor from PyLS

I'm not sure if we should use wave underline, it is not showing as much as expected.

However the single line underline is more visible,

Issue(s) Resolved

Fixes #9472

Affirmation

By submitting this Pull Request or typing my (user)name below,
I affirm the Developer Certificate of Origin
with respect to all commits and content included in this PR,
and understand I am releasing the same under Spyder's MIT (Expat) license.

I certify the above statement is true and correct: steff456

[pep8speaks]

Hello @steff456! Thanks for updating this PR. We checked the lines you've touched for PEP 8 issues, and found:

• In the file spyder/plugins/editor/widgets/codeeditor.py:

Line 1473:25: E128 continuation line under-indented for visual indent

Comment last updated at 2019-06-18 15:47:07 UTC

[ccordoba12]

I'd say we should go with a single underline instead of the wavy one.

@goanpeca, what do you say?

[goanpeca]

Sure @ccordoba12 let's try that one out

[ccordoba12]

@steff456, is this ready to go?

[steff456]

@steff456, is this ready to go?

I will put the single underline and it will be ready to go

[ccordoba12]

Thanks a lot @steff456!