adopt VSCode's new js/ts config prefix

[jasonlyu123]

Description

tracking support for https://code.visualstudio.com/updates/v1_110#_unified-javascript-and-typescript-settings

Proposed solution

Read from the new config section

Alternatives

No response

Additional Information, eg. Screenshots

No response

[jasonlyu123]

Looked into it, and it's hard to support in the language server. Both the old and new setting sections have a default value. So we can't use a null check to fall back. In the VSCode TypeScript extension, the priority check is done by checking where the config is defined and if it has changed the default setting. However, the config in LSP is already merged without the info on where it's defined. It's only possible with a custom LSP method, and only supporting it in VSCode.