Add a diagnostic on `foo: In(1)` being typo'd as `foo: 1`

[whitequark]

E.g.:

class AsconAEAD128(wiring.Component):
    err: 1

    def elaborate(self, platform):
        m = Module()
        m.d.comb += self.err.eq(1)
        return m

outputs

  File "/home/whitequark/Projects/amaranth-ascon/amaranth_ascon/_aead128.py", line 138, in elaborate
    m.d.comb += self.err.eq(1)
                ^^^^^^^^
AttributeError: 'AsconAEAD128' object has no attribute 'err'

but could output

  File "/home/whitequark/Projects/amaranth-ascon/amaranth_ascon/_aead128.py", line 138, in elaborate
    m.d.comb += self.err.eq(1)
                ^^^^^^^^
AttributeError: 'AsconAEAD128' object has no attribute 'err' (did you intend to annotate 'err: In(1)' or 'err: Out(1)'?)