Report validation warnings/errors in HTML page after the grid

[tidoust]

The schedule command returns an HTML page with the created grid. That grid highlights some of the validation warnings and errors but not all of them. Validation issues that cannot be reported in the grid are summarized in the initial table, but that just gives people a number of warnings and errors. Individual issues should be reported after the grid so that readers can understand what happened (and why there are warnings/errors).