REST API Pages: fix links of endpoints-available-for-github-apps page (…

…github#27425)

lib/rest/index.js

@@ -1,5 +1,7 @@
 import { fileURLToPath } from 'url'
+import fs from 'fs'
 import path from 'path'
+
 import { readCompressedJsonFileFallback } from '../read-json-file.js'
 import renderContent from '../render-content/index.js'
 import getMiniTocItems from '../get-mini-toc-items.js'
@@ -9,6 +11,8 @@ import languages from '../languages.js'
 const __dirname = path.dirname(fileURLToPath(import.meta.url))
 const schemasPath = path.join(__dirname, 'static/decorated')
 const ENABLED_APPS_FILENAME = path.join(__dirname, 'static/apps/enabled-for-apps.json')
+const contentPath = path.join(process.cwd(), 'content/rest')
+
 /*
   Loads the schemas from the static/decorated folder into a single
   object organized by version.
@@ -32,6 +36,13 @@ Object.keys(languages).forEach((language) => {
   })
 })
 
+export const categoriesWithoutSubcategories = fs
+  .readdirSync(contentPath)
+  .filter((file) => {
+    return file.endsWith('.md') && !file.includes('index.md') && !file.includes('README.md')
+  })
+  .map((filteredFile) => filteredFile.replace('.md', ''))
+
 const restOperations = new Map()
 export default async function getRest(version, category, subCategory) {
   const openApiVersion = getOpenApiVersion(version)