Use tags array in highlight function

[Hopding]

Description

This PR causes the highlighting function to use the last element of a node's tags array property as its type. This change depends on the parser updates introduced in https://github.com/maryvilledev/codesplain/pull/76#pullrequestreview-35816890, so https://github.com/maryvilledev/codesplain/pull/76#pullrequestreview-35816890 should be merged before this PR.

Motivation and Context

Fixes #442. We want more specific information about certain nodes, such as function calls and boolean values.

Checklist:

• [x] My code follows the code style of this project.
• [x] I have added tests to cover my changes.
• [x] All new and existing tests passed.

Screenshots (if appropriate):