Fix IntervalArray docstrings with missing period in the summary

[datapythonista]

Same as #132, but for other docstrings:

pandas.arrays.IntervalArray.left: Summary does not end with a period
pandas.arrays.IntervalArray.right: Summary does not end with a period
pandas.arrays.IntervalArray.closed: Summary does not end with a period
pandas.arrays.IntervalArray.mid: Summary does not end with a period
pandas.arrays.IntervalArray.length: Summary does not end with a period
pandas.arrays.IntervalArray.is_non_overlapping_monotonic: Summary does not end with a period
pandas.arrays.IntervalArray.from_tuples: Summary does not end with a period
pandas.arrays.IntervalArray.set_closed: Summary does not end with a period
pandas.arrays.IntervalArray.to_tuples: Summary does not end with a period

[sparalic]

@datapythonista I will take up this one

[sparalic]

@datapythonista it's complete.

[datapythonista]

great, thanks, you can close this issue once the PR is merged.

[sparalic]

will do!

[datapythonista]

@sparalic you can also check this notebook that @TanyaaCJain created: https://github.com/python-sprints/pandas-mentoring/blob/master/notebooks/docstring_error_frequency.ipynb

The histogram at the end are all errors that we can help fix. We are now working on SS03, one of the somehow small bars. :)

[sparalic]

@datapythonista great, I will look for others as well.

[sparalic]

closed, merged in pandas #28043