feat: extended markdown
- Added support for h1: Formatter.Header1(string)
- Added support for h2: Formatter.Header2(string)
- Added support for h3: Formatter.Header3(string)
- Added support for single quotes: Formatter.SingleQuote(string)
- Added support for multiline quotes: Formatter.MultiQuote(string)
- Added support for simple list: Formatter.SimpleList(string[])
See https://support.discord.com/hc/en-us/articles/210298617 for more information.