Feature request: inline code

[robintw]

It would be great if stitch could deal with inline code, included within a Markdown chunk. For example Pweave allows you to use syntax like: <%=2+2%> inside a Markdown chunk, and this will be replaced with the result of the expression.

I've also seen this done with nicer syntax, for example {{2+2}} when using jinja-style templating.

[kiwi0fruit]

Stitch already has it in it's own way: via using Markdown() method of Jupyter.

[kiwi0fruit]

From Pandoctools examples:

```py
from IPython.display import Markdown
import math
Markdown(f'''

Markdown text with formula: $α^{{{math.pi:1.3f}}}$.
It works because of the `Markdown ()`.

''')