Add failing test for issue #6724
Fix markdown rendering with inline maths

The mistune 'text' regex was capturing into math expressions in some
cases. The fix was to modify it to stop at a $ sign, giving the inline
math regex a chance to capture that.

Closes gh-6724
Don't show the Qt console tooltip when no object was found
Make fallback for get() explicit
Merge pull request #6729 from takluyver/qtconsole-empty-tooltip

Don't show the Qt console tooltip when no object was found
Merge pull request #6727 from takluyver/i6724

Fix markdown to HTML conversion with inline maths
 Fix issue #5877

This PR prevent to have lists environments inside the headings cells
which break latex code.

- First, the function `markdown2latex` has been changed in order to accept a markup keyword for pandoc reader, default to `markdown` as before.
- Headings cells are treated with markup `markdown_strict+tex_math_dollars` to remove enhancements of pandoc for lists and add math support
- Secondly, `prevent_list_blocks` filter escape characters `. - * +` in headings cells to prevent `enumerate` or `itemize` environments in latex sections

Test files accessible at: <https://gist.github.com/benjaminabel/4a40d1300dcf087c8695>