This also fixes another bug with inline wrappers. Namely,
we should only add inline wrappers if a block node has
both non-block (inline or text) and block children.
This was a workaround to be able to build on case-insensitive file
systems where it might get confused about <string.h> vs <String.h>.
Let's just not support building that way, so String.h can have an
objectively nicer name. :^)
