New Issue: Incremental 'make docs' build can hide actual errors

18405, "bradcray", "Incremental 'make docs' build can hide actual errors", "2021-09-12T03:03:35Z"

In its new incremental form, make docs can hide actual errors because
it doesn't re-build relevant files. For example, say that one file, A.rst
refers to a label/anchor in a second file B.rst. If someone is editing
B.rst and edits that label/anchor out, only B.rst is rebuilt and no
problems are found. But when A.rst is eventually re-built, it will break
because it can no longer resolve the cross-file link.