AoT captures too many keys

[dimbleby]

#!/usr/bin/env python3

import tomlkit


doc = tomlkit.parse("a.b = 1\nc.d = 2\n")
aot = tomlkit.aot()
t = tomlkit.table()
t["x"] = 9
aot.append(t)
doc["a"] = aot
print(tomlkit.dumps(doc))

result

[[a]]
x = 9
c.d = 2

in which c.d has wrongly been captured by the array of tables.

Similar in flavour to other recent bug reports and fixes, I expect the fix will be nearby too.