[docs] Add shebang section for scripts (#11553)

<!--
Thank you for contributing to uv! To help us out with reviewing, please
consider the following:

- Does this pull request include a summary of the change? (See below.)
- Does this pull request include a descriptive title?
- Does this pull request include references to any relevant issues?
-->

## Summary

Documentation only. Adds a section in scripts.md about running uv
scripts with a shebang line

## Test Plan

n/a

---------

Co-authored-by: Zanie Blue <contact@zanie.dev>

docs/guides/scripts.md

@@ -217,6 +217,39 @@ print(Point)
 is not installed — see the documentation on [Python versions](../concepts/python-versions.md) for
 more details.
 
+## Using a shebang to create an executable file
+
+A shebang can be added to make a script executable without using `uv run` — this makes it easy to
+run scripts that are on your `PATH` or in the current folder.
+
+For example, create a file called `greet` with the following contents
+
+```python title="greet"
+#!/usr/bin/env -S uv run --script
+
+print("Hello, world!")
+```
+
+Ensure that your script is executable, e.g., with `chmod +x greet`, then run the script:
+
+```console
+$ ./greet
+Hello, world!
+```
+
+Declaration of dependencies is also supported in this context, for example:
+
+```python title="example"
+#!/usr/bin/env -S uv run --script
+# /// script
+# requires-python = ">=3.12"
+# dependencies = ["httpx"]
+# ///
+import httpx
+
+print(httpx.get("https://example.com"))
+```
+
 ## Using alternative package indexes
 
 If you wish to use an alternative [package index](../configuration/indexes.md) to resolve