Highlights Scaladoc macros that are wrapped in braces

The new rule needs to be placed in front of the normal macro rule
because it starts with the same identifier but contains more
characters to detect. Thus it needs to be detected first.

Fixes #1001836
Merge pull request #499 from sschaef/t1001836-scaladoc-macro-braces

Highlights Scaladoc macros that are wrapped in braces