Set correct scope attributes on rowheaders tables (#35999)

Co-authored-by: Rachael Sewell <rachmari@github.com>

lib/render-content/create-processor.js

@@ -29,12 +29,25 @@ import doctocatLinkIcon from './doctocat-link-icon.js'
 // see https://github.com/unifiedjs/unified/issues/79
 const wrapperForImages = () =>
   wrapInElement({ selector: 'ol > li img', wrapper: 'span.procedural-image-wrapper' })
-const wrapperForTables = () =>
+const wrapperForRowheadersThead = () =>
+  wrapInElement({
+    selector: '.rowheaders thead th',
+    wrapper: 'th',
+    // This moves what it finds in the selector inside the wrapper.
+    rewrite: true,
+    wrapperAdditionalAttributes: {
+      scope: 'col',
+    },
+  })
+const wrapperForRowheadersTbody = () =>
   wrapInElement({
     selector: '.rowheaders tbody tr td:first-child',
     wrapper: 'th',
     // This moves what it finds in the selector inside the wrapper.
     rewrite: true,
+    wrapperAdditionalAttributes: {
+      scope: 'row',
+    },
   })
 
 export default function createProcessor(context) {
@@ -57,7 +70,8 @@ export default function createProcessor(context) {
     })
     .use(raw)
     .use(wrapperForImages)
-    .use(wrapperForTables)
+    .use(wrapperForRowheadersThead)
+    .use(wrapperForRowheadersTbody)
     .use(rewriteImgSources)
     .use(rewriteAssetImgTags)
     .use(rewriteLocalLinks, context)