Clarify Postgres spec usage of ignore_databases

postgres/assets/configuration/spec.yaml

@@ -241,6 +241,8 @@ files:
         A list of databases to ignore. No metrics or statement samples will be collected for these databases.
         Each value can be a plain string or a Postgres pattern. If you want to ignore the postgres database,
         set collect_default_database to false in addition to adding it to this array.
+        This setting does not apply to schema collection, column statistics, or autodiscovery; instead use
+        the specific include/exclude settings nested under those configurations.
         For more information on how patterns work, see https://www.postgresql.org/docs/12/functions-matching.html
       value:
         type: array

postgres/changelog.d/24922.added

@@ -0,0 +1 @@
+Clarify Postgres spec usage of ignore_databases

postgres/datadog_checks/postgres/data/conf.yaml.example

@@ -176,6 +176,8 @@ instances:
     ## A list of databases to ignore. No metrics or statement samples will be collected for these databases.
     ## Each value can be a plain string or a Postgres pattern. If you want to ignore the postgres database,
     ## set collect_default_database to false in addition to adding it to this array.
+    ## This setting does not apply to schema collection, column statistics, or autodiscovery; instead use
+    ## the specific include/exclude settings nested under those configurations.
     ## For more information on how patterns work, see https://www.postgresql.org/docs/12/functions-matching.html
     #
     # ignore_databases: