templatekw: reference predecessor node id as {node} in map operation More predecessor-depending values will be populated by the next patch.

highlight: put pygments import inside demandimport.deactivated I tripped on some weirdness relating to _thread vs threading way down in a dep of highlight recently. I'm not really sure why I'm only just seeing this defect now, but experimentally this fixes the problem, and shouldn't cause any load-time slowness for people until pygments is actually about to be used since highlight.highlight is still lazily loaded in the highlight/__init__.py file.