fix(gatsby-remark-autolink-headers): option to disable "position: relative" when icon is not present (#27022)

Author: parulc7

packages/gatsby-remark-autolink-headers/src/__tests__/__snapshots__/index.js.snap

@@ -225,7 +225,6 @@ Object {
   "data": Object {
     "hProperties": Object {
       "id": "heading-uno",
-      "style": "position:relative;",
     },
     "htmlAttributes": Object {
       "id": "heading-uno",

packages/gatsby-remark-autolink-headers/src/index.js

@@ -60,9 +60,9 @@ module.exports = (
     patch(data, `hProperties`, {})
     patch(data.htmlAttributes, `id`, id)
     patch(data.hProperties, `id`, id)
-    patch(data.hProperties, `style`, `position:relative;`)
 
     if (icon !== false) {
+      patch(data.hProperties, `style`, `position:relative;`)
       const label = id.split(`-`).join(` `)
       const method = isIconAfterHeader ? `push` : `unshift`
       node.children[method]({