Bad inference for `mtable`

The following MathML gets inferred to be "lines". It shouldn't. You want to navigate and hear each column.
```

```

If were a matrix or determinant, there would be some bracketing characters around it. The case of a "naked" `mtable` that should be read as a table probably isn't that common. Still, it would be nice to figure out a way to distinguish between this and something else that really is a "line".