Mark text as highlighted

[jnnkB]

Is your feature request related to a problem? Please describe. I would like to be able to highlight some text inside this text editor.

Describe the solution you'd like I would like to have this implemented in a similar way to the bold text tool. On the markdown side ==highlighted text== should probably be used since that seems to be what most other tools use.^[1]

[1]: https://stackoverflow.com/questions/25104738/text-highlight-in-markdown