DOC: Docstring pandas index all any
Checklist for the pandas documentation sprint (ignore this if you are doing
an unrelated PR):

- [X] PR title is "DOC: update the <your-function-or-method> docstring"
- [ ] 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>`
- [X] It has been proofread on language by another sprint participant

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

```
################################################################################
######################### Docstring (pandas.Index.any) #########################
################################################################################

Return whether any element is True.

Parameters
----------
*args
    These parameters will be passed to numpy.any.
**kwargs
    These parameters will be passed to numpy.any.

Returns
-------
any : bool or array_like (if axis is specified)
    A single element array_like may be converted to bool.

        See Also
        --------
        pandas.Index.all : Return whether all elements are True.

        Notes
        -----
        Not a Number (NaN), positive infinity and negative infinity
        evaluate to True because these are not equal to zero.

        Examples
        --------
        >>> index = pd.Index([0, 1, 2])
        >>> index.any()
        True

        >>> index = pd.Index([0, 0, 0])
        >>> index.any()
        False

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

Errors found:
        No extended summary found
        Errors in parameters section
                Parameters {'args', 'kwargs'} not documented
                Unknown parameters {'**kwargs', '*args'}
                Parameter "*args" has no type
                Parameter "**kwargs" has no type
```

```
################################################################################
######################### Docstring (pandas.Index.all) #########################
################################################################################

Return whether all elements are True.

Parameters
----------
*args
    These parameters will be passed to numpy.all.
**kwargs
    These parameters will be passed to numpy.all.

Returns
-------
all : bool or array_like (if axis is specified)
    A single element array_like may be converted to bool.

        See Also
        --------
        pandas.Index.any : Return whether any element is True.

        Notes
        -----
        Not a Number (NaN), positive infinity and negative infinity
        evaluate to True because these are not equal to zero.

        Examples
        --------
        >>> index = pd.Index([1, 2, 3])
        >>> index.all()
        True

        >>> index = pd.Index([0, 1, 2])
        >>> index.all()
        False

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

Errors found:
        No extended summary found
        Errors in parameters section
                Parameters {'kwargs', 'args'} not documented
                Unknown parameters {'**kwargs', '*args'}
                Parameter "*args" has no type
                Parameter "**kwargs" has no type
```

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.

# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/20168?src=pr&el=h1) Report
> :exclamation: No coverage uploaded for pull request base (`master@ec631ce`). [Click here to learn what that means](https://docs.codecov.io/docs/error-reference#section-missing-base-commit).
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/20168/graphs/tree.svg?src=pr&token=eZ4WkYLtcO&width=650&height=150)](https://codecov.io/gh/pandas-dev/pandas/pull/20168?src=pr&el=tree)

```diff
@@            Coverage Diff            @@
##             master   #20168   +/-   ##
=========================================
  Coverage          ?   91.72%           
=========================================
  Files             ?      150           
  Lines             ?    49155           
  Branches          ?        0           
=========================================
  Hits              ?    45089           
  Misses            ?     4066           
  Partials          ?        0
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.11% <100%> (?)` | |
| #single | `41.85% <100%> (?)` | |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/20168?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/indexes/base.py](https://codecov.io/gh/pandas-dev/pandas/pull/20168/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9iYXNlLnB5) | `96.67% <100%> (ø)` | |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/20168?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/20168?src=pr&el=footer). Last update [ec631ce...23c2c3d](https://codecov.io/gh/pandas-dev/pandas/pull/20168?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 Thanks @alinde1!