[vscode] vscode.extension.contributes.configuration can be array

[svenefftinge]

What it does

Many VS Code extensions contribute the configuration object wrapped in an array.
See https://github.com/microsoft/vscode/blob/master/src/vs/workbench/api/common/configurationExtensionPoint.ts#L131-L137

Fixes #6072

How to test

1. start the application with the following tomcat vscode extension
2. open the preferences using the menu item File > Settings > Open Preferences
3. there should be a new category Tomcat with the preferences:
   3.1. tomcat.workspace
   3.2. tomcat.restart_when_http(s)_port_change

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

[svenefftinge]

Examples (test with):

• https://github.com/adashen/vscode-tomcat/blob/develop/package.json#L339
• https://github.com/microsoft/vscode-maven/blob/master/package.json#L399

[svenefftinge]

@a1994846931931 could you check if this fixes #6046, too?

[tom-shan]

LGTM

[akosyakov]

Tested that preference definitions as an object and array are supported.

Object:

Array:

[a1994846931931]

@a1994846931931 could you check if this fixes #6046, too?

@svenefftinge Thank you svenefftinge! But I don't think they are related since I've confirmed that the contributes.configuration of the plugin that I tested is not an Array.