* HTML reader: Handle cite attribute for quotes. If a `<q>` tag has a `cite` attribute, we interpret it as a Quoted element with an inner Span. Closes#5798
* Refactor url canonicalization into a helper function
* Modify HTML writer to handle quote with cite.
[0]: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/q
add `onlySimpleTableCells` to `Text.Pandoc.Shared`
[API change]
This fixes an inconsistency in the HTML reader, which did not treat tables with `<p>` inside cells as simple.
* Added underlineSpan builder function. This can be easily updated if needed. The purpose is for Readers to transform underlines consistently.
* Docx Reader: Use underlineSpan and update test
* Org Reader: Use underlineSpan and add test
* Textile Reader: Use underlineSpan and add test case
* Txt2Tags Reader: Use underlineSpan and update test
* HTML Reader: Use underlineSpan and add test case
