docs: improvements to API reference intro sections (#9397)

- Improve intro sections of API reference to utilize divided columns
- Improve the content of the intro sections
- Add a new Workflows section to explain the workflows badge and how to use it
- Fixes to headings and add anchor for copying the link to a section
- Fixes responsiveness of intro sections on mobile devices
- Other: fix loading not showing when a sidebar category is opened.

Closes DOCS-932, DOCS-934, DOCS-937

Preview: https://api-reference-v2-git-docs-api-ref-intro-fixes-medusajs.vercel.app/v2/api/store

www/apps/api-reference/components/Section/Container/index.tsx

@@ -14,9 +14,12 @@ const SectionContainer = forwardRef<HTMLDivElement, SectionContainerProps>(
     ref
   ) {
     return (
-      <div className={clsx("relative pb-7", !noTopPadding && "pt-7")} ref={ref}>
+      <div
+        className={clsx("relative pb-4 md:pb-7", !noTopPadding && "pt-7")}
+        ref={ref}
+      >
         {children}
-        {!noDivider && <SectionDivider className="-left-1.5 lg:!-left-4" />}
+        {!noDivider && <SectionDivider className="-left-1.5 lg:!-left-full" />}
       </div>
     )
   }