go back to using path.join

Author: sarahs

lib/all-products.js

@@ -47,7 +47,7 @@ sortedProductIds.forEach(productId => {
   const toc = slash(path.join(dir, 'index.md'))
   const { data } = frontmatter(fs.readFileSync(toc, 'utf8'))
   const applicableVersions = getApplicableVersions(data.versions, toc)
-  const href = removeFPTFromPath(`/${applicableVersions[0]}/${productId}`)
+  const href = removeFPTFromPath(slash(path.join('/', applicableVersions[0], productId)))
 
   internalProducts[productId] = {
     id: productId,