`@!has` (and `@!matches`) with two arguments used to treat the second
argument as a literal string of HTML code. Now, that feature has been
renamed into `@!hasraw` (and `@!matchesraw`), and the arity-2 `@!has`
version is an error.
These uses thought the second argument was being treated as an XPath, as
with the arity-3 version, but in fact was being treated as literal HTML.
Because these were checking for the *absence* of the string, the tests
silently did nothing -- an XPath string won't ever be showing up in the
test's generated HTML!
Use h3 and h4 for the variant name and the "Fields" subheading.
Remove the "of T" part of the "Fields" subheading.
Remove border-bottom from "Fields" subheading.
Move docblock below "Fields" listing.
