Include `nrow()` and `ncol()` in `length_test_linter()`

Would it make sense to also cover `nrow(x == )` and `ncol(x == )` in length_test_linter()`?

I was recently bitten by this and I don't think there is any more reasons this should be valid than for `length(x == )`.

https://github.com/search?q=%2F\bn(row|col)\([^\(\)\[\]]%2B%3D%3D\s*\d%2B\)%2F+language%3AR&type=code