DOC: update the Period.qyear docstring
Checklist for the pandas documentation sprint (ignore this if you are doing
an unrelated PR):

 PR title is "DOC: update the <your-function-or-method> docstring"

 

- [x] The validation script passes: `scripts/validate_docstrings.py <your-function-or-method>`
- [x] The PEP8 style check passes: `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] The html version looks good: `python doc/make.py --single <your-function-or-method>`
- [ ] It has been proofread on language by another sprint participant

Please include the output of the validation script below between the "```" ticks:

```
(pandas_dev) ani@ani-Lenovo-G50-80:~/github/pandas/scripts$ python validate_docstrings.py  

- [ ] pandas.Period.qyear

################################################################################
####################### Docstring (pandas.Period.qyear)  #######################
################################################################################

Return a year of the given date.

This function simply find the year of the given date that period fallsin.

Returns
-------
int

See Also
--------
Period.qyear :Return the year of the date

Examples
--------
>>> p = pd.Period("2014-9-21", freq="A")
>>> p.qyear
2014

################################################################################
################################## Validation ##################################
################################################################################

```

If the validation script still gives errors, but you think there is a good reason
to deviate in this case (and there are certainly such cases), please state this
explicitly.