src/vs/base/browser/ui/keybindingLabel/keybindingLabel.ts/KeybindingLabel/createKeyElement
class KeybindingLabel:	private createKeyElement(label: string, extraClass = ''): HTMLElement {
		const keyElement = $('span.monaco-keybinding-key' + extraClass, undefined, label);
		this.keyElements.add(keyElement);

		if (this.labelBackground) {
			keyElement.style.backgroundColor = this.labelBackground;
		}
		if (this.labelBorder) {
			keyElement.style.borderColor = this.labelBorder;
		}
		if (this.labelBottomBorder) {
			keyElement.style.borderBottomColor = this.labelBottomBorder;
		}
		if (this.labelShadow) {
			keyElement.style.boxShadow = `inset 0 -1px 0 ${this.labelShadow}`;
		}

		return keyElement;
	}