src/vs/workbench/contrib/remote/browser/tunnelView.ts/validateInput
	function validateInput(value: string, canElevate: boolean): { content: string; severity: Severity } | null {
		if (!value.match(/^[0-9]+$/)) {
			return { content: invalidPortString, severity: Severity.Error };
		} else if (Number(value) >= maxPortNumber) {
			return { content: invalidPortNumberString, severity: Severity.Error };
		} else if (canElevate && isPortPrivileged(Number(value))) {
			return { content: requiresSudoString, severity: Severity.Info };
		}
		return null;
	}