Include nested parse for `ref` role text

Describe the bug {ref}`*vectorization* <sec:vectorization>` should result in “vectorization” as a link and italicized. The current result is:

<a class="reference internal" href="ch1.html#sec-vectorization"><span class="std std-ref">*vectorization*</span></a>.</p>

To Reproduce To use an example already at hand:

1. Open to docs/examples/wealth_dynamics_md.md
2. Modify the area around line 56 to add a label and a reference:

(sec:lorenz)=                                                                   
## Lorenz Curves and the Gini Coefficient                                       
                                                                                
Here is a reference to {ref}`*Lorenz* <sec:lorenz>`, with emphasis!

1. Navigate to docs/ and build: make html
2. View the output: <browser> _build/html/examples/wealth_dynamics_md.html

Expected behavior The emphasis syntax within a role should result in a functioning link that is also italicized.

Screenshots N/A

Environment (please complete the following information):

• Python Version [e.g. 3.7.1] 3.8.2
• Package Version [e.g. 0.1.0] MyST-Parser 0.5.1

Additional context I noticed that tests/test_syntax/test_ast.py has a test_role which appears to test internal emphasis. I’m not as familiar with pytest as I need to be, so I had trouble parsing the test suite to figure out exactly what was happening - either way, it doesn’t appear the test covers the full conversion from MyST syntax->HTML.

[chrisjsewell]

It seems markup is now correctly rendered in markdown-style links

only for external links, see #152

[akhmerov]

It seems markup is now correctly rendered in markdown-style links. Since the ref-style links are probably wontfix, should this issue be closed?

[I am **bold** and mathy $\int$](https://example.com)