New keywords are added, this corresponds to the pull request:
https://github.com/KDE/syntax-highlighting/pull/23
I also added a test file, which I obtained from: https://github.com/agda/agda/blob/master/examples/syntax/highlighting/Test.agda
When I saw the test file, I noticed some problems in the highlighting of floating point. So I fixed this, according to the lexical described in the Agda documentation: https://agda.readthedocs.io/en/latest/language/lexical-structure.html#literals
In addition, I added folded and ##Alerts in the comments.