Simplify doc generation infra

PUBLISHED_FROM=80e77fda1c358294f251ca77d3dd64e8ca9160e5

docs/build-options/intro.md

@@ -1,5 +1,10 @@
 ---
 title: Build Options
+items:
+  - { type: file, name: enabling-flags.md }
+  - { type: file, name: disabling-flags.md }
+  - { type: file, name: platform-spec.md }
+  - { type: file, name: tunables.md }
 ---
 
 Mongoose source code ships in a single .c file that contains functionality

docs/build-options/items.json

@@ -1,9 +0,0 @@
-{
-  "items": [
-    { "type": "markdown", "name": "intro.md" },
-    { "type": "markdown", "name": "enabling-flags.md" },
-    { "type": "markdown", "name": "disabling-flags.md" },
-    { "type": "markdown", "name": "platform-spec.md" },
-    { "type": "markdown", "name": "tunables.md" }
-  ]
-}