docs: Fix bullet list formatting in installation.md

Add blank line before bullet list after "Expected output" text.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: dimitri-yatsenko

src/how-to/installation.md

@@ -38,6 +38,7 @@ print(dj.__version__)
 ```
 
 **Expected output for this documentation:**
+
 - `2.0.0` or higher — You're ready to follow this documentation
 - `0.14.x` or lower — You have the stable version, use [legacy docs](https://datajoint.github.io/datajoint-python) instead