Explicitly highlight all the section headers (#18)

* Explicitly highlight all the section headers

Due to how language injection works these headers can sometimes become
un-highlighted. This should fix that by highlighting them in the
highlighting annotator and not just the syntax highlighter.

Fixes #17

Allow macros within changelog body (#15)

This resolves issue #11 where the %autochangelog macro is throwing a
parsing error.

Bump version to 2.0.1 and set release notes

Update changelog again

Bump version to 1.2.0 and set release notes