Bug: Code style linting is ignored after Spyder restart

Issue Report Checklist

• Searched the issues page for similar reports
• Read the relevant sections of the Spyder Troubleshooting Guide and followed its advice
• Reproduced the issue after updating with conda update spyder (or pip, if not using Anaconda)
• Could not reproduce inside jupyter qtconsole (if console-related)
• Tried basic troubleshooting (if a bug/error)
  • Restarted Spyder
  • Reset preferences with spyder --reset
  • Reinstalled the latest version of Anaconda
  • Tried the other applicable steps from the Troubleshooting Guide
• Completed the Problem Description, Steps to Reproduce and Version sections below

Problem Description

The far left part of the editor displays yellow triangles that indicated pycodestyle warnings. When I disable some of these warnings with e.g. Tools -> Preferences -> Completion and linting -> Code Style [x] Enable code style linting -> Ignore the following warnings: “W291” the yellow triangles disappear as desired. The problem: When I restart Spyder the yellow warnings are still displays, even though the [x] Enable code style linting is still checked and the list of ignored warnings is not changed.

What steps reproduce the problem?

1. Tools -> Preferences -> Completion and linting -> Code Style [x] Enable code style linting -> Ignore the following warnings: “W291”
2. Restart spyder

What is the expected output? What do you see instead?

I expect to not see the yellow triangles that correspond to the e.g. “W291” But they are still there.

Paste Traceback/Error Below (if applicable)

N.A.

## Versions
* Spyder version: 4.1.5 None
* Python version: 3.7.7 64-bit
* Qt version: 5.9.7
* PyQt5 version: 5.9.2
* Operating System: Linux 5.4.0-48-generic

### Dependencies

# Mandatory:
atomicwrites >=1.2.0           :  1.4.0 (OK)
chardet >=2.0.0                :  3.0.4 (OK)
cloudpickle >=0.5.0            :  1.6.0 (OK)
diff_match_patch >=20181111    :  20200713 (OK)
intervaltree                   :  None (OK)
IPython >=4.0                  :  7.18.1 (OK)
jedi =0.17.1                   :  0.17.1 (OK)
keyring                        :  None (OK)
nbconvert >=4.0                :  6.0.2 (OK)
numpydoc >=0.6.0               :  1.1.0 (OK)
parso =0.7.0                   :  0.7.0 (OK)
pexpect >=4.4.0                :  4.8.0 (OK)
pickleshare >=0.4              :  0.7.5 (OK)
psutil >=5.3                   :  5.7.2 (OK)
pygments >=2.0                 :  2.7.0 (OK)
pylint >=1.0                   :  2.6.0 (OK)
pyls >=0.34.0;<1.0.0           :  0.35.0 (OK)
qdarkstyle >=2.8               :  2.8.1 (OK)
qtawesome >=0.5.7              :  0.7.2 (OK)
qtconsole >=4.6.0              :  4.7.7 (OK)
qtpy >=1.5.0                   :  1.9.0 (OK)
rtree >=0.8.3                  :  0.9.4 (OK)
sphinx >=0.6.6                 :  3.2.1 (OK)
spyder_kernels >=1.9.4;<1.10.0 :  1.9.4 (OK)
watchdog                       :  None (OK)
xdg >=0.26                     :  0.26 (OK)
zmq >=17                       :  19.0.2 (OK)

# Optional:
cython >=0.21                  :  0.29.21 (OK)
matplotlib >=2.0.0             :  3.1.2 (OK)
numpy >=1.7                    :  1.15.4 (OK)
pandas >=0.13.1                :  1.1.2 (OK)
scipy >=0.17.0                 :  1.4.1 (OK)
sympy >=0.7.3                  :  1.6.2 (OK)

[dalthviz]

Hi @pawelusc maybe a fix for this was done in #13828. What happens if you restart the LSP using the option in the status bar?

Any new info that you could provide us is greatly appreciated 😃

[dalthviz]

Done @ccordoba12