src/vs/editor/contrib/unicodeHighlighter/browser/unicodeHighlighter.ts/excludeCharFromBeingHighlighted
async function excludeCharFromBeingHighlighted(configurationService: IConfigurationService, charCodes: number[]) {
	const existingValue = configurationService.getValue(unicodeHighlightConfigKeys.allowedCharacters);

	let value: Record<string, boolean>;
	if ((typeof existingValue === 'object') && existingValue) {
		value = existingValue as any;
	} else {
		value = {};
	}

	for (const charCode of charCodes) {
		value[String.fromCodePoint(charCode)] = true;
	}

	await configurationService.updateValue(unicodeHighlightConfigKeys.allowedCharacters, value, ConfigurationTarget.USER);
}