refactor(theme): use JSON-LD instead of microdata for blog structured data (#9669)

Co-authored-by: Joshua Chen <sidachen2003@gmail.com>
Co-authored-by: sebastien <lorber.sebastien@gmail.com>

packages/docusaurus-plugin-content-blog/src/index.ts

@@ -42,6 +42,7 @@ import type {
   BlogTags,
   BlogContent,
   BlogPaginated,
+  BlogMetadata,
 } from '@docusaurus/plugin-content-blog';
 
 export default async function pluginContentBlog(
@@ -182,6 +183,7 @@ export default async function pluginContentBlog(
         blogArchiveComponent,
         routeBasePath,
         archiveBasePath,
+        blogTitle,
       } = options;
 
       const {addRoute, createData} = actions;
@@ -257,6 +259,15 @@ export default async function pluginContentBlog(
         ),
       );
 
+      const blogMetadata: BlogMetadata = {
+        blogBasePath: normalizeUrl([baseUrl, routeBasePath]),
+        blogTitle,
+      };
+      const blogMetadataPath = await createData(
+        `blogMetadata-${pluginId}.json`,
+        JSON.stringify(blogMetadata, null, 2),
+      );
+
       // Create routes for blog entries.
       await Promise.all(
         blogPosts.map(async (blogPost) => {
@@ -276,6 +287,9 @@ export default async function pluginContentBlog(
               sidebar: aliasedSource(sidebarProp),
               content: metadata.source,
             },
+            context: {
+              blogMetadata: aliasedSource(blogMetadataPath),
+            },
           });
 
           blogItemsToMetadata[id] = metadata;