DOC: Remove repeated duplicated word
Minor fixes to docs ✏️ 
# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/19546?src=pr&el=h1) Report
> Merging [#19546](https://codecov.io/gh/pandas-dev/pandas/pull/19546?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/ed10bf618b93726c61ed9b3ebbc3031416bc1263?src=pr&el=desc) will **not change** coverage.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/19546/graphs/tree.svg?height=150&width=650&token=eZ4WkYLtcO&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/19546?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master   #19546   +/-   ##
=======================================
  Coverage    91.6%    91.6%           
=======================================
  Files         150      150           
  Lines       48750    48750           
=======================================
  Hits        44657    44657           
  Misses       4093     4093
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `89.97% <ø> (ø)` | :arrow_up: |
| #single | `41.75% <ø> (ø)` | :arrow_up: |


------

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