Make og:type article for markdown pages (#3146) (#3147)

src/components/MarkdownPage/MarkdownPage.js

@@ -74,6 +74,7 @@ const MarkdownPage = ({
       }}>
       <TitleAndMetaTags
         ogDescription={ogDescription}
+        ogType="article"
         canonicalUrl={createCanonicalUrl(markdownRemark.fields.slug)}
         title={`${titlePrefix}${titlePostfix}`}
       />

src/components/TitleAndMetaTags/TitleAndMetaTags.js

@@ -17,6 +17,7 @@ type Props = {
   title: string,
   ogDescription: string,
   canonicalUrl: string,
+  ogType: string,
 };
 
 // only provide alternate links to pages in languages where 95-100% of core content has been translated
@@ -45,11 +46,16 @@ const defaultPage = canonicalUrl => {
   return canonicalUrl.replace(urlRoot, 'https://reactjs.org');
 };
 
-const TitleAndMetaTags = ({title, ogDescription, canonicalUrl}: Props) => {
+const TitleAndMetaTags = ({
+  title,
+  ogDescription,
+  canonicalUrl,
+  ogType = 'website',
+}: Props) => {
   return (
     <Helmet title={title}>
       <meta property="og:title" content={title} />
-      <meta property="og:type" content="website" />
+      <meta property="og:type" content={ogType} />
       {canonicalUrl && <meta property="og:url" content={canonicalUrl} />}
       <meta property="og:image" content="https://reactjs.org/logo-og.png" />
       <meta