Minor follow-on to PR #1334 (Fix enum value's __int__ returning non-int when underlying type is bool or of char type)

[rwgk]

This PR just removes two comments, changes one, and tweaks a test for consistency with a comment.

The main motivation for creating this PR was this comment:

    assert m.ScopedCharEnum.Positive.__getstate__() == 1  # return type is long in py2.x

The comment made me wonder if the .__getstate__() is an accommodation for Python 2 (that we'd need to take care of later when we purge Python 2 support).
But replacing it with int(assert m.ScopedCharEnum.Positive) == 1 and running the CI also works on all platforms.
Therefore I'm now thinking that the intent was to actually exercise .__getstate__(). Is that correct?
In that case I think the comment is misleading and better removed.

While I was at it:

This comment seems completely redundant (therefore more likely to be confusing than helpful):

assert int(m.ScopedChar16Enum.Zero) == 0  # int() call should successfully return

I made this change because the original comment seemed unclear to me:

-        # Enum should construct with a int, even with char underlying type
-        m.ScopedWCharEnum("0")
+        # Even if the underlying type is char, only an int can be used to construct the enum:
+        m.ScopedCharEnum("0")

I rewrote it according to my understanding. Is that correct?
While I was at that, I removed the W in WChar, to make the test match the comment more closely.

[rwgk]

@Vigilans Could you please take a look at these tweaks and approve it it looks good to you, or let me know any suggestions?

[Vigilans]

I've written down my original intent of each test/comment to help clarifying the story and help you decide whether they should be removed or tweaked. I agree with your comments and am fine with any change if it is misleading.

[Vigilans]

The intent of this test was that when __int__() returns a non-int, int() call will throw a error:

>>> Player.black.__int__()
'\x01'

>>> int(Player.black)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: __int__ returned non-int (type str)

So I wrote this call in the test and expected it to successfully return.

[rwgk]

Thanks. I think that is clear just from the test code itself.

[Vigilans]

Yes, the intent of this test is to exercise __getstate__() call (along with __hash__() call). The intent of this comment was because __getstate__() and __hash__() returns a long type in python 2.x, so

assert type(m.ScopedCharEnum.Positive.__getstate__()) is int

will fail in python 2.x platforms. So I tested them by comparing with 1.

[rwgk]

Aha! :-)
I changed this, using if env.PY2, so that we get what you originally had in mind for Python 3.

The if env.PY2 branch will get purged when we clean out Python 2 support in a few months.

Unfortunately our pre-commit checks (black, flake8) get upset about type(...) is long. To not make things overly complicated for Python 2 I just kept your == 1 test for Python 2.

[Vigilans]

The intent of this test, I remembered, was that when enum's underlying type is char, then pybind11's enum not only returns a string, but also could only be constructed with a string. So I wrote a test here to expect it to throw a TypeError instead of returning successfully.

[rwgk]

@Vigilans thanks for the clarifications!