Parse all four levels of \dot

[hersle]

Julia seems to have up to four possible levels of \dot-ting.
I encountered errors when rendering some of these that were not implemented.

[gustaphe]

Do you mean that this was an error before this implementation, or does some engine (like MathJax) not render \dddot correctly?

Either way, LGTM. It's generally fine for Latexify to make output that some engines might not recognize in edge cases, as long as it is valid LaTeX.

[hersle]

Before the implementation, in VSCode:

render(latexify("τ⃛")) # \tau\dddot

gives