Merge pull request #25869 from kamipo/specificiation_id_was_renamed_to_spec_name

`specificiation_id` was renamed to `spec_name`

activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb

@@ -896,7 +896,7 @@ def clear_all_connections!
       # for (not necessarily the current class).
       def retrieve_connection(spec_name) #:nodoc:
         pool = retrieve_connection_pool(spec_name)
-        raise ConnectionNotEstablished, "No connection pool with id '#{spec_name}' found." unless pool
+        raise ConnectionNotEstablished, "No connection pool with '#{spec_name}' found." unless pool
         conn = pool.connection
         raise ConnectionNotEstablished, "No connection for '#{spec_name}' in connection pool" unless conn
         conn