DOC: file obj for to_csv must be newline=''
- [x] closes #25048

# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/25624?src=pr&el=h1) Report
> Merging [#25624](https://codecov.io/gh/pandas-dev/pandas/pull/25624?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/e28ae70ba8bd8b4174143543d1660421bc67887b?src=pr&el=desc) will **decrease** coverage by `3.22%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/25624/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/25624?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #25624      +/-   ##
==========================================
- Coverage   91.26%   88.03%   -3.23%     
==========================================
  Files         173      173              
  Lines       52968    56259    +3291     
==========================================
+ Hits        48339    49528    +1189     
- Misses       4629     6731    +2102
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `89.83% <ø> (ø)` | :arrow_up: |
| #single | `41.9% <ø> (+0.18%)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/25624?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/generic.py](https://codecov.io/gh/pandas-dev/pandas/pull/25624/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ2VuZXJpYy5weQ==) | `76.65% <ø> (-17.01%)` | :arrow_down: |
| [pandas/core/groupby/groupby.py](https://codecov.io/gh/pandas-dev/pandas/pull/25624/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ3JvdXBieS9ncm91cGJ5LnB5) | `74.28% <0%> (-22.93%)` | :arrow_down: |
| [pandas/plotting/\_core.py](https://codecov.io/gh/pandas-dev/pandas/pull/25624/diff?src=pr&el=tree#diff-cGFuZGFzL3Bsb3R0aW5nL19jb3JlLnB5) | `66.38% <0%> (-17.16%)` | :arrow_down: |
| [pandas/core/arrays/sparse.py](https://codecov.io/gh/pandas-dev/pandas/pull/25624/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL3NwYXJzZS5weQ==) | `76.66% <0%> (-15.52%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/25624/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `81.68% <0%> (-15.12%)` | :arrow_down: |
| [pandas/core/indexes/base.py](https://codecov.io/gh/pandas-dev/pandas/pull/25624/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9iYXNlLnB5) | `88.08% <0%> (-8.49%)` | :arrow_down: |
| [pandas/core/base.py](https://codecov.io/gh/pandas-dev/pandas/pull/25624/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYmFzZS5weQ==) | `90.96% <0%> (-6.81%)` | :arrow_down: |
| [pandas/plotting/\_misc.py](https://codecov.io/gh/pandas-dev/pandas/pull/25624/diff?src=pr&el=tree#diff-cGFuZGFzL3Bsb3R0aW5nL19taXNjLnB5) | `35.03% <0%> (-3.66%)` | :arrow_down: |
| [pandas/core/config.py](https://codecov.io/gh/pandas-dev/pandas/pull/25624/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvY29uZmlnLnB5) | `84.45% <0%> (-2.6%)` | :arrow_down: |
| ... and [3 more](https://codecov.io/gh/pandas-dev/pandas/pull/25624/diff?src=pr&el=tree-more) | |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/25624?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/25624?src=pr&el=footer). Last update [e28ae70...9541062](https://codecov.io/gh/pandas-dev/pandas/pull/25624?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/25624?src=pr&el=h1) Report
> Merging [#25624](https://codecov.io/gh/pandas-dev/pandas/pull/25624?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/e28ae70ba8bd8b4174143543d1660421bc67887b?src=pr&el=desc) will **decrease** coverage by `3.22%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/25624/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/25624?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #25624      +/-   ##
==========================================
- Coverage   91.26%   88.03%   -3.23%     
==========================================
  Files         173      173              
  Lines       52968    56259    +3291     
==========================================
+ Hits        48339    49528    +1189     
- Misses       4629     6731    +2102
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `89.83% <ø> (ø)` | :arrow_up: |
| #single | `41.9% <ø> (+0.18%)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/25624?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/generic.py](https://codecov.io/gh/pandas-dev/pandas/pull/25624/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ2VuZXJpYy5weQ==) | `76.65% <ø> (-17.01%)` | :arrow_down: |
| [pandas/core/groupby/groupby.py](https://codecov.io/gh/pandas-dev/pandas/pull/25624/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ3JvdXBieS9ncm91cGJ5LnB5) | `74.28% <0%> (-22.93%)` | :arrow_down: |
| [pandas/plotting/\_core.py](https://codecov.io/gh/pandas-dev/pandas/pull/25624/diff?src=pr&el=tree#diff-cGFuZGFzL3Bsb3R0aW5nL19jb3JlLnB5) | `66.38% <0%> (-17.16%)` | :arrow_down: |
| [pandas/core/arrays/sparse.py](https://codecov.io/gh/pandas-dev/pandas/pull/25624/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL3NwYXJzZS5weQ==) | `76.66% <0%> (-15.52%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/25624/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `81.68% <0%> (-15.12%)` | :arrow_down: |
| [pandas/core/indexes/base.py](https://codecov.io/gh/pandas-dev/pandas/pull/25624/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9iYXNlLnB5) | `88.08% <0%> (-8.49%)` | :arrow_down: |
| [pandas/core/base.py](https://codecov.io/gh/pandas-dev/pandas/pull/25624/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYmFzZS5weQ==) | `90.96% <0%> (-6.81%)` | :arrow_down: |
| [pandas/plotting/\_misc.py](https://codecov.io/gh/pandas-dev/pandas/pull/25624/diff?src=pr&el=tree#diff-cGFuZGFzL3Bsb3R0aW5nL19taXNjLnB5) | `35.03% <0%> (-3.66%)` | :arrow_down: |
| [pandas/core/config.py](https://codecov.io/gh/pandas-dev/pandas/pull/25624/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvY29uZmlnLnB5) | `84.45% <0%> (-2.6%)` | :arrow_down: |
| ... and [3 more](https://codecov.io/gh/pandas-dev/pandas/pull/25624/diff?src=pr&el=tree-more) | |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/25624?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/25624?src=pr&el=footer). Last update [e28ae70...9541062](https://codecov.io/gh/pandas-dev/pandas/pull/25624?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 Restarted to avoid the DST failures.

Just the sparse failure now, which is fixed on master. Should be OK to merge @jorisvandenbossche .