src/vs/workbench/api/common/extHostTypes.ts/Hover/constructor
class Hover:	constructor(
		contents: vscode.MarkdownString | vscode.MarkedString | (vscode.MarkdownString | vscode.MarkedString)[],
		range?: Range
	) {
		if (!contents) {
			throw new Error('Illegal argument, contents must be defined');
		}
		if (Array.isArray(contents)) {
			this.contents = contents;
		} else {
			this.contents = [contents];
		}
		this.range = range;
	}