We've been incorrectly validating (or not validating at all) the
requirement that certain blocks be followed by a name string, to prohibit
e.g. this:
variable {}
and:
variable = ""
Before this change we were catching this for most constructs only if
there were no _valid_ blocks of the same name in the same file. For
modules in particular, we were not catching this at all.
Now we detect this for all kinds of block (resources had a pre-existing
check, so aren't touched here) and produce a different error message
depending on which of the above incorrect forms are used.
This fixes#13575.
