Report the presence of form content in the properties section

[rdeltour]

From @mattgarrish:

A number of WCAG SCs focus on support for interaction with form elements (operability, error handling, etc.). I don't need to know where form elements occur so much as whether they occur to allow those SC to be filtered out when they don't apply. I really just need a boolean that says whether any elements were encountered (form, input, button select, datalist, textarea, output, progress, meter). It's going to be imperfect, as it won't account for custom aria controls, but I suspect those are extremely rare.