Add deno usage info to getting-started.mdx (#1014)

Author: philhawksworth

src/routes/solid-start/getting-started.mdx

@@ -86,6 +86,12 @@ pnpm i
 bun install
 ```
 </div>
+
+<div id="deno">
+```bash frame="none"
+deno install
+```
+</div>
 </TabsCodeBlocks>
 
 After this command has finished, your new SolidStart application is ready to go!
@@ -118,6 +124,12 @@ pnpm dev
 bun dev
 ```
 </div>
+
+<div id="deno">
+```bash frame="none"
+deno task dev
+```
+</div>
 </TabsCodeBlocks>
 
 Your application should now be running locally on port 3000.