Inline formatting should be ignored in inline code fences

[alercah]

vim-markdown does not properly recognize that inline code fences override other inline formats, see for example Example 334 from the GitHub spec which is Example 332 in CommonMark. If you put these into a Markdown file in vim, it incorrectly highlights an emphasis block over foo` . Likewise, underscores in inline code blocks are frequently highlighted in red.

This is frustrating enough to make me turn off code highlighting when working with documents that use a lot of inline code with symbols in them.

Escaping the symbols satisfies the highligher, but causes incorrect rendering as escapes are generally not recognized by Markdown parsers inside inline code either.