DOC: Fix a typo in dsintro.rst
thanks! : ) # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/15877?src=pr&el=h1) Report
> Merging [#15877](https://codecov.io/gh/pandas-dev/pandas/pull/15877?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/4cb730e95353f414bb47f571a69781746bd3e84b?src=pr&el=desc) will **decrease** coverage by `0.02%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/15877/graphs/tree.svg?width=650&src=pr&token=eZ4WkYLtcO&height=150)](https://codecov.io/gh/pandas-dev/pandas/pull/15877?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #15877      +/-   ##
==========================================
- Coverage   90.98%   90.96%   -0.03%     
==========================================
  Files         143      143              
  Lines       49479    49479              
==========================================
- Hits        45020    45009      -11     
- Misses       4459     4470      +11
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `88.72% <ø> (-0.01%)` | :arrow_down: |
| #single | `40.63% <ø> (-0.11%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/15877?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/15877?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `25% <0%> (-58.34%)` | :arrow_down: |
| [pandas/util/testing.py](https://codecov.io/gh/pandas-dev/pandas/pull/15877?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvdGVzdGluZy5weQ==) | `80.66% <0%> (-0.19%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/15877?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `97.56% <0%> (-0.1%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/15877?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/15877?src=pr&el=footer). Last update [4cb730e...b78e21c](https://codecov.io/gh/pandas-dev/pandas/pull/15877?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments). # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/15877?src=pr&el=h1) Report
> Merging [#15877](https://codecov.io/gh/pandas-dev/pandas/pull/15877?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/4cb730e95353f414bb47f571a69781746bd3e84b?src=pr&el=desc) will **decrease** coverage by `0.02%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/15877/graphs/tree.svg?width=650&src=pr&token=eZ4WkYLtcO&height=150)](https://codecov.io/gh/pandas-dev/pandas/pull/15877?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #15877      +/-   ##
==========================================
- Coverage   90.98%   90.96%   -0.03%     
==========================================
  Files         143      143              
  Lines       49479    49479              
==========================================
- Hits        45020    45009      -11     
- Misses       4459     4470      +11
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `88.72% <ø> (-0.01%)` | :arrow_down: |
| #single | `40.63% <ø> (-0.11%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/15877?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/15877?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `25% <0%> (-58.34%)` | :arrow_down: |
| [pandas/util/testing.py](https://codecov.io/gh/pandas-dev/pandas/pull/15877?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvdGVzdGluZy5weQ==) | `80.66% <0%> (-0.19%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/15877?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `97.56% <0%> (-0.1%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/15877?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/15877?src=pr&el=footer). Last update [4cb730e...b78e21c](https://codecov.io/gh/pandas-dev/pandas/pull/15877?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).