documentation: add syntax highlighting (via google code prettify)
metomi/rose#376: fix trigger for null-value missing parent
metomi/rose#376: further fix
metomi/rose#376: handle missing section trigger of non-section settings
Merge pull request #377 from benfitzpatrick/doc.syntax-highlighting

rose documentation: add syntax highlighting (via Google Code Prettify)
Merge pull request #378 from benfitzpatrick/376.config-edit-trigger-latent

metomi/rose#376: fix trigger for null-value missing parent