Open Radar

 
Summary:
According to the the Markup Formatting Reference documents (https://developer.apple.com/library/content/documentation/Xcode/Reference/xcode_markup_formatting_ref/), I should be able to have nested bold and italic delimiters, ascii art markdown-like tables, and multiple heading levels via #, ##, ###, etc. However, when trying to implement any of the above, the Quick Help pane simply doesn't show anything. I've also noticed that adding any HTML tags produces the same results. Last, but not least, `- SeeAlso:` callouts do not render, regardless of comment marker used, indentation, etc.

Steps to Reproduce:
1. Open Xcode.
2. Create a "Markup" comment, using either the multiline marker style (i.e. `/** Markup here */` or the single-line marker style (i.e. `/// Markup here`).
3. Add the following: `I like **bold _text_** and I cannot lie!`.
4. Alternatively, try to create a subheading by adding `## Part 2`.
5. For even more fun, add a line and type `- SeeAlso: otherFunc(_:)`. You can also try to add an all-lowercase version like this: `- seealso: otherFunc(_:)`.
6. Finally, using standard markdown formatting, add a table like so: 

/// | Header 1 | Header 2 | 
/// | ------------ | ------------- |
/// | Cell 1      | Cell 2        |

Expected Results:
After performing the above steps, one should see formatted output in the Quick Help sidebar pane and/or the Quick Help popover view.

Actual Results:
Instead, none of the markup is rendered. The only visible items are: a label that says "No Quick Help" and a "Search Documentation" button.