Remove embedded code stuff from HTML.

We're not going to have embedded PHP or whatever in the HTML that appears in
JavaDoc comments.

If I don't end up throwing away all this TextMate stuff in favor of proper
syntax from javac, I'll improve these grammars to handle <pre>{@code foo}</pre>
blocks, which *are* nested code, but nested Java code, and other goodies.
Don't match the < and > as part of a generic type.

I'm too used to not seeing them matched and I think it's nice to make the
different components of a generic type more starkly visible. (The latter of
course being a rationalization for the former.)
More zations; also strip old when adding new.