Table cell count consistency check

[lloeki]

This could produce a cell count consistency warning:

aze | qsd | wxc
----|-----
123 | 456

or

aze | qsd
----|-----|-----
123 | 456 | 678

The former is not rendered by parsers at all, but the latter is rendered, only exceeding cells are missing.

[JacksonTian]

Hope to see it.