[clang-tools-extra] [clang-tidy] Add misc-shadowed-namespace-function check (PR #168406)

[via cfe-commits]

github-actions[bot] wrote:

<!--LLVM CODE LINT COMMENT: doc8-->


:warning: RST documentation linter, doc8 found issues in your code. :warning:

<details>
<summary>
You can test this locally with the following command:
</summary>

```bash
doc8 -q clang-tools-extra/docs/clang-tidy/checks/misc/shadowed-namespace-function.rst clang-tools-extra/docs/clang-tidy/checks/list.rst
```

</details>

<details>
<summary>
View the output from doc8 here.
</summary>

```
clang-tools-extra/docs/clang-tidy/checks/misc/shadowed-namespace-function.rst:6: D002 Trailing whitespace
clang-tools-extra/docs/clang-tidy/checks/misc/shadowed-namespace-function.rst:24: D002 Trailing whitespace
```

</details>


https://github.com/llvm/llvm-project/pull/168406