… in fieldname

We should prevent highlighting if a field is anything but a text or keyword field.
However, someone might implement a custom field type that has text and still want to
highlight on that. We cannot know in advance if the highlighter will be able to
highlight such a field and so we do the following:
If the field is only highlighted because the field matches a wildcard we assume
it was a mistake and do not process it.
If the field was explicitly given we assume that whoever issued the query knew
what they were doing and try to highlight anyway.

closes elastic#17537