regression: isNamedTuple(MyGenericTuple[int]) is false, should be true

[timotheecour]

/cc @cooldome #13347 introduced a regression:
isNamedTuple(MyGenericTuple[int]) is now false

Example

type Foo3[T] = tuple[x:int, y: T]
echo isNamedTuple(Foo3[int8])

Current Output

false

Expected Output

true

Additional Information

• root cause of CI failure for replace old problematic isNamedTuple implementation by TypeTrait isNamedTuple in dollars.nim #13347
• regression introduced in distinctBase type trait for distinct types #13031
• the old implementation i wrote didn't have this issue:

proc isNamedTuple(T: typedesc): bool =
  when T isnot tuple: result = false
  else:
    var t: T
    for name, _ in t.fieldPairs:
      when name == "Field0":
        return compiles(t.Field0)
      else:
        return true
    return false

however it had subtle issues so #13031 is good, but the code in semmagic.nim needs to fix this