feat: add data for @scope (#693)

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### Description

The `@scope` at-rule shipped in Chrome 118 (see
https://chromestatus.com/feature/5100672734199808). This PR adds data
for it.

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### Motivation

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Author: chrisdavidmills

css/at-rules.json

@@ -467,6 +467,14 @@
     "status": "experimental",
     "mdn_url": "https://developer.mozilla.org/docs/Web/CSS/@property"
   },
+  "@scope": {
+    "syntax": "@scope [(<scope-start>)]? [to (<scope-end>)]? {\n  <rule-list>\n}",
+    "groups": [
+      "CSS Conditional Rules"
+    ],
+    "status": "standard",
+    "mdn_url": "https://developer.mozilla.org/docs/Web/CSS/@scope"
+  },
   "@scroll-timeline": {
     "syntax": "@scroll-timeline <timeline-name> { <declaration-list> }",
     "interfaces": [