docs: Use higher-quality image in the header (#22195)

Improved image quality of docs site logo at top.

Prior Change: 
<img width="159" alt="SCR-20241218-konx"
src="https://github.com/user-attachments/assets/18c936e8-958d-4970-98e2-8dd1ad3a0a89"
/>
Post Change: 
<img width="177" alt="SCR-20241218-kojm"
src="https://github.com/user-attachments/assets/0b874ac2-7193-44ec-9634-b91a71c53864"
/>

Release Notes:

- N/A

---------

Co-authored-by: Danilo Leal <[email protected]>

docs/theme/index.hbs

@@ -148,7 +148,7 @@
 
                     <header class="menu-title">
                         <a href="/">
-                            <img src="https://zed.dev/logo_wordmark_36.webp" alt="Zed Industries" style="height: 28px;">
+                            <img src="https://zed.dev/logo_wordmark_1500.webp" alt="Zed Industries" style="height: 28px;">
                         </a>
                     </header>