Fix: Remove trailing comma in rust-analyzer linkedProjects configuration

This commit fixes a JSON syntax issue in the rust-analyzer configuration file. The trailing comma after the last item in the "rust-analyzer.linkedProjects" list has been removed to ensure the file adheres to the JSON standard. Without this fix, tools processing the JSON file could encounter errors.

.vscode/settings.json

@@ -1,6 +1,6 @@
 {
     "rust-analyzer.linkedProjects": [
         "./rust/main/Cargo.toml",
-        "./rust/sealevel/Cargo.toml",
-    ],
-}
+        "./rust/sealevel/Cargo.toml"
+    ]
+}