Pairs of numbers incorrectly concatenated with cdot = false

[kapple19]

I initially opened this issue in Symbolics.jl since I superficially noticed this issue occurs with @variables and not Exprs or Strings fed to latexify.

Basically the @latexrecipes defined in Symbolics.jl/src/latexify_recipes.jl all set cdot --> false, which avoids placing \cdots everywhere.

There isn't a simple solution to this, but I'm happy to look into the challenge of designing an algorithm and non-breaking (additive) API that places \cdots in some nicely disambiguating places.