Delete get_nai_pool method description from database_api documentation

_data/apidefinitions/database_api.yml

@@ -2410,62 +2410,6 @@
     - '{"jsonrpc":"2.0", "method":"database_api.find_smt_tokens", "params":{"symbols":[],"ignore_precision":false}, "id":1}'
     client_docs:
     - "[hive-ruby](https://www.rubydoc.info/gems/hive-ruby/Hive/Api)"
-  - api_method: database_api.get_nai_pool
-    since: Mysterious Future
-    purpose: |
-      Return an array of Numeric Asset Identifier (NAI) available to be used for new SMT to be created.
-
-      See: [Numerical Asset Identifiers]({{ 'https://github.com/steemit/smt-whitepaper/blob/master/smt-manual/manual.md' | archived_url }}#numerical-asset-identifiers)
-    parameter_json: "{}"
-    expected_response_json: |
-      {
-        "nai_pool": [
-          {
-            "nai": "@@456173464",
-            "precision": 0
-          },
-          {
-            "nai": "@@483570188",
-            "precision": 0
-          },
-          {
-            "nai": "@@262899546",
-            "precision": 0
-          },
-          {
-            "nai": "@@651791780",
-            "precision": 0
-          },
-          {
-            "nai": "@@695960327",
-            "precision": 0
-          },
-          {
-            "nai": "@@337834146",
-            "precision": 0
-          },
-          {
-            "nai": "@@465565260",
-            "precision": 0
-          },
-          {
-            "nai": "@@528352042",
-            "precision": 0
-          },
-          {
-            "nai": "@@326426201",
-            "precision": 0
-          },
-          {
-            "nai": "@@960128623",
-            "precision": 0
-          }
-        ]
-      }
-    curl_examples:
-    - '{"jsonrpc":"2.0", "method":"database_api.get_nai_pool", "params":{}, "id":1}'
-    client_docs:
-    - "[hive-ruby](https://www.rubydoc.info/gems/hive-ruby/Hive/Api)"
   - api_method: database_api.list_smt_contributions
     since: Mysterious Future
     purpose: |