Hierarchical tags are now available
We just got hierarchical tags. A tag can have one or more children, and when you search on a tag you can either search just that tag or also search its children. This gives us another way to organize content.
This feature was proposed on the Judaism site; you can see more background there. (This was also a longstanding request on Mi Yodeya, and its absence led to some cumbersome tag names.) This seems like it could be useful here, and we can do it opportunistically: we're not building a whole tree, but in cases where tags are clearly specializations of other tags, we can now link them together.
As a demonstration, I've created one child of the technical-writing tag. Please use this meta post to discuss whether and where we'd like to create other tag relationships.
A tag can have only one parent; this isn't C++. :-)