Restore Oxford comma in README (#40518)

Marshall Bowers created

We use Oxford commas in this household.

Release Notes:

- N/A

Change summary

README.md | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

Detailed changes

README.md 🔗

@@ -9,7 +9,7 @@ Welcome to Zed, a high-performance, multiplayer code editor from the creators of
 
 ### Installation
 
-On macOS, Linux and Windows you can [download Zed directly](https://zed.dev/download) or [install Zed via your local package manager](https://zed.dev/docs/linux#installing-via-a-package-manager).
+On macOS, Linux, and Windows you can [download Zed directly](https://zed.dev/download) or [install Zed via your local package manager](https://zed.dev/docs/linux#installing-via-a-package-manager).
 
 Other platforms are not yet available: