doc: Update Snapshot list and detail API reference to match schema validation

Update the snapshot list and list-detail API reference to reflect the validated query parameters

Change-Id: I782787cfcfe863398c4b4cf52145bd3b15b6fe05
Signed-off-by: Marco Wehrhahn <marco.wehrhahn@gmail.com>

api-ref/source/parameters.yaml

@@ -724,6 +724,16 @@ snapshot_id_query:
   in: query
   required: false
   type: string
+snapshot_metadata_query:
+  description: |
+    Filters the list of snapshots by metadata. The value must be a string
+    representation of a key-value mapping that can be parsed by the API.
+    For example: ``{"env": "prod"}`` or ``{"key": "value"}``. If the
+    value cannot be parsed, the API responds with ``400 Bad Request``.
+  in: query
+  required: false
+  type: string
+  min_version: 2.73
 sort_dir:
   description: |
     The direction to sort a list of resources. A valid

api-ref/source/snapshots.inc

@@ -68,8 +68,18 @@ Request
 
    - project_id: project_id_path
    - all_tenants: all_tenants_query
+   - limit: limit
+   - offset: offset
+   - sort_key: sort_key
+   - sort_dir: sort_dir
+   - name: name_query
+   - description: description_query
+   - status: snapshot_status
+   - share_id: snapshot_share_id
+   - size: snapshot_size
    - name~: name_inexact_query
    - description~: description_inexact_query
+   - metadata: snapshot_metadata_query
    - with_count: with_count_snapshot_query
 
 Response parameters
@@ -113,8 +123,18 @@ Request
 
    - project_id: project_id_path
    - all_tenants: all_tenants_query
+   - limit: limit
+   - offset: offset
+   - sort_key: sort_key
+   - sort_dir: sort_dir
+   - name: name_query
+   - description: description_query
+   - status: snapshot_status
+   - share_id: snapshot_share_id
+   - size: snapshot_size
    - name~: name_inexact_query
    - description~: description_inexact_query
+   - metadata: snapshot_metadata_query
    - with_count: with_count_snapshot_query
 
 Response parameters