NumberStyle: do not automatically convert numbers with_html.

In some cases, we have numbers which are _already_ in the appropriate
style. Most notably, when considering the user input values from which we
made the style determinations in the first place.

This fixes the bug, but is still unsatisfying because we would need
to convert both in and out in order to do better input styling.
add missing semicolon to attribution, comment out empty category and topic
templates: add more guidance information.

- Explicity label both category and topics to be completed with a link
  to appropriate section of the metadata docs
- Request tests for example queries and some negative samples.
Merge pull request #681 from mwmiller/html_styling

NumberStyle: do not automatically convert numbers with_html.
Merge pull request #698 from duckduckgo/zaahir/template-fix

add missing semicolon to attribution, comment out empty category and topic