src/vs/editor/contrib/codeAction/codeActionCommands.ts/SourceAction/constructor
class SourceAction:	constructor() {
		super({
			id: sourceActionCommandId,
			label: nls.localize('source.label', "Source Action..."),
			alias: 'Source Action...',
			precondition: ContextKeyExpr.and(EditorContextKeys.writable, EditorContextKeys.hasCodeActionsProvider),
			contextMenuOpts: {
				group: '1_modification',
				order: 2.1,
				when: ContextKeyExpr.and(
					EditorContextKeys.writable,
					contextKeyForSupportedActions(CodeActionKind.Source)),
			},
			description: {
				description: 'Source Action...',
				args: [{ name: 'args', schema: argsSchema }]
			}
		});
	}