markers: update problem decorations

[vince-fugnitto]

What it does

The pull-request updates our marker decorations for trees (most notably the navigator) to only render decorations for diagnostics with error or warning severity.

How to test

1. include the following test plugin: code-actions-sample-0.0.2.vsix.zip.

2. create a workspace folder that is not under version control (so we do not get git decorations).

3. create a file in that folder

4. use the created folder as the workspace

5. in the file, type:

   1
   2
   3
   4
   

6. each line in the file should produce a different severity diagnostic in the problems view:

7. confirm the navigator has an error decoration for the file.
8. delete line 1 - confirm the navigator has a warning decoration for the file.
9. delete line 2 - confirm the navigator has no decorations for the file since there is none left that have a high enough severity.

Review checklist

• As an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• As a reviewer, I agree to behave in accordance with the review guidelines

Signed-off-by: vince-fugnitto [email protected]

[msujew]

Looks good to me 👍

• Errors and warnings continue to display decorators in the navigator
• Information diagnostics do not display decorators