Reflect the length hint in the total of the progress bar

[bartbroere]

Before this pull request, if self.iterable had a length hint, it would be reflected in the length of the tqdm object, but the progress bar would not show it as a total.

Reproduction:

import string

from more_itertools import consume
from tqdm import tqdm


class ExampleGenerator:

    def __iter__(self):
        for letter in string.ascii_letters:
            yield letter

    def __length_hint__(self):
        return len(string.ascii_letters)


consume(tqdm(ExampleGenerator()))

Output before this PR:

52it [00:00, 1703936.00it/s]

Output after this PR:

100%|██████████| 52/52 [00:00<00:00, 1603704.47it/s]

Related issues: #1068 #228 #1132