update error response for non-snapshots (#860)

specification/resources/snapshots/responses/not_a_snapshot.yml

@@ -0,0 +1,18 @@
+description: Bad Request
+
+headers:
+  ratelimit-limit:
+    $ref: '../../../shared/headers.yml#/ratelimit-limit'
+  ratelimit-remaining:
+    $ref: '../../../shared/headers.yml#/ratelimit-remaining'
+  ratelimit-reset:
+    $ref: '../../../shared/headers.yml#/ratelimit-reset'
+
+content:
+  application/json:
+    schema:
+      $ref: '../../../shared/models/error.yml'
+    example:
+      id: bad_request
+      message: the resource is not a snapshot
+      request_id: bbd8d7d4-2beb-4be1-a374-338e6165e32d

specification/resources/snapshots/snapshots_delete.yml

@@ -20,6 +20,9 @@ responses:
   '204':
     $ref: '../../shared/responses/no_content.yml'
 
+  '400':
+    $ref: 'responses/not_a_snapshot.yml'
+
   '401':
     $ref: '../../shared/responses/unauthorized.yml'
 

specification/resources/snapshots/snapshots_get.yml

@@ -19,6 +19,9 @@ responses:
   '200':
     $ref: 'responses/snapshots_existing.yml'
 
+  '400':
+    $ref: 'responses/not_a_snapshot.yml'
+
   '401':
     $ref: '../../shared/responses/unauthorized.yml'