Typo - `strings`

Also, most of these placeholders are also available as properties or derived from them.  The missing pieces are `state`, `startDatetime`, `endDateTime`, and `duration`.  It would be simpler, I think, to use interpolation for `startDescription` and `endDescription`.  The missing properties could either be added as build properties on the completion of a build (in a separate pull req).  What do you think?