Update of ED report from new reffy run

Using reffy commit 18.1.2.

Author: reffy-bot

ed/index.json

@@ -1,7 +1,7 @@
 {
   "type": "crawl",
   "title": "Reffy crawl",
-  "date": "2024-12-30T06:43:09.842Z",
+  "date": "2024-12-30T12:48:48.601Z",
   "options": {
     "fallback": "ed/index.json",
     "output": "report",
@@ -1576,7 +1576,7 @@
       "headings": "headings/font-metrics-api-1.json",
       "ids": "ids/font-metrics-api-1.json",
       "cddl": [],
-      "error": "Error: Loading https://drafts.css-houdini.org/font-metrics-api-1/ triggered HTTP status 504\n    at processSpecification (file:///home/runner/work/webref/webref/node_modules/reffy/src/lib/util.js:481:19)\n    at async crawlSpec (file:///home/runner/work/webref/webref/node_modules/reffy/src/lib/specs-crawler.js:107:22)\n    at async processSpec (file:///home/runner/work/webref/webref/node_modules/reffy/src/lib/specs-crawler.js:380:22)\n    at async ThrottledQueue.runThrottled (file:///home/runner/work/webref/webref/node_modules/reffy/src/lib/throttled-queue.js:78:22)\n    at async Promise.all (index 16)\n    at async crawlList (file:///home/runner/work/webref/webref/node_modules/reffy/src/lib/specs-crawler.js:401:21)"
+      "error": "Error: Loading https://drafts.css-houdini.org/font-metrics-api-1/ triggered HTTP status 504\n    at processSpecification (file:///home/runner/work/webref/webref/node_modules/reffy/src/lib/util.js:481:19)\n    at async crawlSpec (file:///home/runner/work/webref/webref/node_modules/reffy/src/lib/specs-crawler.js:107:22)\n    at async processSpec (file:///home/runner/work/webref/webref/node_modules/reffy/src/lib/specs-crawler.js:380:22)\n    at async ThrottledQueue.runThrottled (file:///home/runner/work/webref/webref/node_modules/reffy/src/lib/throttled-queue.js:78:22)"
     },
     {
       "url": "https://drafts.csswg.org/css-backgrounds-4/",