fix(specs): add type: object to 3 schemas

Explicit is better than implicit, so this commit adds `type: object`
to 3 schemas standardEntries, userData, and source.

Author: kai687

specs/search/paths/rules/common/schemas.yml

@@ -121,6 +121,7 @@ consequence:
         required:
           - objectID
     userData:
+      type: object
       description: |
         A JSON object with custom data that will be appended to the `userData` array in the response.
         This object isn't interpreted by the API and is limited to 1 kB of minified JSON.

specs/search/paths/vault/common/schemas.yml

@@ -5,6 +5,7 @@ sources:
     $ref: '#/source'
 
 source:
+  type: object
   description: Source.
   required:
     - source