Reorder docs manifest and rename to Script Optimization. (vercel#26874)

So there's _conformance_ between the other docs / optimizations.

docs/manifest.json

@@ -29,6 +29,10 @@
               "title": "Font Optimization",
               "path": "/docs/basic-features/font-optimization.md"
             },
+            {
+              "title": "Script Optimization",
+              "path": "/docs/basic-features/script.md"
+            },
             {
               "title": "Static File Serving",
               "path": "/docs/basic-features/static-file-serving.md"
@@ -52,10 +56,6 @@
             {
               "title": "Supported Browsers and Features",
               "path": "/docs/basic-features/supported-browsers-features.md"
-            },
-            {
-              "title": "Script",
-              "path": "/docs/basic-features/script.md"
             }
           ]
         },