Translate \cdots to cdots in eqn writer

[RobertGoulding]

In converting from LaTeX math to eqn, \cdots is translated to \[u22EF] (which leaves a blank space when I convert to pdf).

But cdots is a keyword in GNU eqn, which most people will be using, and has exactly the effect of \cdots. (In older Unix eqn, "..." is used for centered dots; but in GNU eqn, they come out as baseline dots).

[jgm]

We actually are using cdots for 22EF. See #200. Maybe you're using an old version?