Syntax errors detected in JSON files do not disappear after they are fixed.

[awshelley-beckman]

• VSCode Version: 1.52.1
• OS Version: Kubuntu 20.04

Steps to Reproduce:

1. Open a .json file
2. Add a trailing comma
3. Observe the red squiggly line, telling you that you have a trailing comma
4. Delete the trailing comma
5. Observe that the red squiggly line has not disappeared.

Does this issue occur when all extensions are disabled?: Yes/No
No.

[vscodebot]

(Experimental duplicate detection)
Thanks for submitting this issue. Please also check if it is already covered by an existing one, like:

• Allow trailing commas in settings JSON when viewed from git stage/index (#97843)

[aeschli]

I am not able to reproduce with no additional extensions.
If you can, please attach a small code snippet that reproduces the issue.

You can try https://code.visualstudio.com/updates/v1_52#_troubleshooting-extension-bisect to find out which extension causes the problem.