normalizeLinkTitle function
Normalizes a link title, including the process of HTML characters decoding and HTML characters escaping.
Implementation
// See the description of these examples:
// https://spec.commonmark.org/0.30/#example-505
// https://spec.commonmark.org/0.30/#example-506
// https://spec.commonmark.org/0.30/#example-507
// https://spec.commonmark.org/0.30/#example-508
String normalizeLinkTitle(String title) =>
escapeHtmlAttribute(decodeHtmlCharacters(title));