Prevent duplicated entries in find() in presence of directory markers

[martindurant]

Fixes #988

@ischurov , can you try this?

[ischurov]

Now I have this output (for the same example as here):

s3fs.__version__='2024.10.0+31.ge8f64a8'
['<test bucket>/a/', '<test bucket>/b', '<test bucket>/b/', '<test bucket>/c/']

Note that the output still differs from what I see if I do not invoke s3.find before s3.ls:

s3fs.__version__='2024.10.0+31.ge8f64a8'
['<test bucket>/a', '<test bucket>/b', '<test bucket>/c']

I don't know whether it is expected behavior or not.

Also, my initial problem with missing directories is still present.

[martindurant]

Hmm, I'll try again when I have the time. I agree the two outputs should be the same... Whether ls() should show the placeholders, I'm not sure, since there're not "within" the listed directory (i.e., "<listed_path>/..."). I should definitely have tests around this!

[martindurant]

@ischurov , the latest commit is my reproducer, so now I should have something concrete I can fix. Part of the problem, is that s3fs will not create any file ending in "/". That seems like a sane, if accidental, safeguard, but also inconvenient for some people.