Merge pull request #4987 from rescript-lang/fix_4985

fix #4985

Author: bobzhang

docs/docson/build-schema.json

@@ -154,8 +154,7 @@
 
                         "type": {
                             "enum": [
-                                "dev",
-                                "lib"
+                                "dev"
                             ]
                         },
                         "files": {