Add document for specifying Python interpreter in tool installation and upgrade commands. (#11598)

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## Summary
Just to add the section for installing and upgrading uv tool, specifying
the Python version, in the document.
Originally, it was planned to add a markdown block (header) for
representation, but it was felt to be a bit redundant, so it ended up
being like this.

close https://github.com/astral-sh/uv/issues/11536

## Test Plan
Run doc server with strict mode in local. (``mkdocs serve -f
mkdocs.public.yml --strict``)

![image](https://github.com/user-attachments/assets/9da66a8b-5423-4937-bc66-ea696ad1ab88)



<!-- How was it tested? -->

---------

Signed-off-by: FishAlchemist <48265002+FishAlchemist@users.noreply.github.com>
Co-authored-by: Zanie Blue <contact@zanie.dev>

docs/guides/tools.md

@@ -237,6 +237,33 @@ To instead upgrade all tools:
 $ uv tool upgrade --all
 ```
 
+## Requesting Python versions
+
+By default, uv will use your default Python interpreter (the first it finds) when when running,
+installing, or upgrading tools. You can specify the Python interpreter to use with the `--python`
+option.
+
+For example, to request a specific Python version when running a tool:
+
+```console
+$ uvx --python 3.10 ruff
+```
+
+Or, when installing a tool:
+
+```console
+$ uv tool install --python 3.10 ruff
+```
+
+Or, when upgrading a tool:
+
+```console
+$ uv tool upgrade --python 3.10 ruff
+```
+
+For more details on requesting Python versions, see the
+[Python version](../concepts/python-versions.md#requesting-a-version) concept page..
+
 ## Next steps
 
 To learn more about managing tools with uv, see the [Tools concept](../concepts/tools.md) page and