Use Doctocat link header style (#21615)

* update autolinkHeadings to use Doctocat link header style

* fix header link test

* update graphql/rest rendering to use doctocat header link

* fix: miniToc issue with stray anchor

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

lib/render-content/create-processor.js

@@ -21,6 +21,7 @@ import rewriteLocalLinks from './plugins/rewrite-local-links.js'
 import useEnglishHeadings from './plugins/use-english-headings.js'
 import rewriteLegacyAssetPaths from './plugins/rewrite-legacy-asset-paths.js'
 import wrapInElement from './plugins/wrap-in-element.js'
+import doctocatLinkIcon from './doctocat-link-icon.js'
 const graphql = HighlightjsGraphql.definer
 
 export default function createProcessor(context) {
@@ -32,7 +33,11 @@ export default function createProcessor(context) {
     .use(remark2rehype, { allowDangerousHtml: true })
     .use(slug)
     .use(useEnglishHeadings, context)
-    .use(autolinkHeadings, { behavior: 'wrap' })
+    .use(autolinkHeadings, {
+      behavior: 'prepend',
+      properties: { ariaHidden: true, tabIndex: -1, class: 'doctocat-link' },
+      content: doctocatLinkIcon,
+    })
     .use(highlight, {
       languages: { graphql, dockerfile, http, groovy, erb, powershell },
       subset: false,