Support Speculation Rules API formatting in HTML (#12882)

* Add script formatting for `speculationrules`

* Fix lint problems

changelog_unreleased/html/12882.md

@@ -0,0 +1,32 @@
+#### Support Speculation Rules API formatting in HTML (#12882 by @sosukesuzuki)
+
+Please read https://web.dev/speculative-prerendering/ for about Speculation Rules API.
+
+<!-- prettier-ignore -->
+```html
+<!-- Input -->
+<script type="speculationrules">
+  {
+   "prerender": [
+  {"source": "list", "urls": ["https://a.test/foo"]}
+  ]
+  }
+</script>
+
+
+<!-- Prettier stable -->
+<script type="speculationrules">
+  {
+   "prerender": [
+  {"source": "list", "urls": ["https://a.test/foo"]}
+  ]
+  }
+</script>
+
+<!-- Prettier main -->
+<script type="speculationrules">
+  {
+    "prerender": [{ "source": "list", "urls": ["https://a.test/foo"] }]
+  }
+</script>
+```

cspell.json

@@ -304,6 +304,7 @@
         "softlines",
         "Sorin",
         "Sosuke",
+        "speculationrules",
         "srcset",
         "Stachowiak",
         "standalones",

src/language-html/utils/index.js

@@ -364,7 +364,10 @@ function _inferScriptParser(node) {
     return "html";
   }
 
-  if (type && (type.endsWith("json") || type.endsWith("importmap"))) {
+  if (
+    (type && (type.endsWith("json") || type.endsWith("importmap"))) ||
+    type === "speculationrules"
+  ) {
     return "json";
   }
 

tests/format/html/script/__snapshots__/jsfmt.spec.js.snap

@@ -171,6 +171,15 @@ End Function
 
 <script lang="unknown">
 </script>
+
+<script type="speculationrules">
+  {
+   "prerender": [
+  {"source": "list", "urls": ["https://a.test/foo"]}
+  ]
+  }
+  </script>
+
 =====================================output=====================================
 <script type="application/ld+json">
   { "json": true }
@@ -208,5 +217,11 @@ End Function
 
 <script lang="unknown"></script>
 
+<script type="speculationrules">
+  {
+    "prerender": [{ "source": "list", "urls": ["https://a.test/foo"] }]
+  }
+</script>
+
 ================================================================================
 `;

tests/format/html/script/script.html

@@ -31,4 +31,12 @@ End Function
 </script>
 
 <script lang="unknown">
-</script>
+</script>
+
+<script type="speculationrules">
+  {
+   "prerender": [
+  {"source": "list", "urls": ["https://a.test/foo"]}
+  ]
+  }
+  </script>