fix(materialize): correct docstring and remove deprecated flag

- Update create_source docstring to reflect actual supported load generators
  (AUCTION, TPCH, MARKETING only; KEY VALUE and DATUMS removed in v26)
- Remove deprecated enable_create_table_from_source flag from compose.yaml
  (flag is for v26 compatibility, tests should work with default behavior)

Author: jasonhernandez

compose.yaml

@@ -565,7 +565,7 @@ services:
     environment:
       MZ_LOG: info
       MZ_TELEMETRY: "false"
-      MZ_SYSTEM_PARAMETER_DEFAULT: "max_tables=1000;enable_load_generator_counter=true;enable_create_table_from_source=true"
+      MZ_SYSTEM_PARAMETER_DEFAULT: "max_tables=1000"
     healthcheck:
       test: ["CMD", "curl", "-f", "localhost:6878/api/readyz"]
       interval: 1s

ibis/backends/materialize/__init__.py

@@ -731,7 +731,7 @@ def create_source(
         """Create a source in Materialize.
 
         This method supports creating sources from various systems including:
-        - Load generators (AUCTION, TPCH, MARKETING, KEY VALUE, DATUMS)
+        - Load generators (AUCTION, TPCH, MARKETING)
         - Kafka/Redpanda message brokers
         - PostgreSQL, MySQL, SQL Server (CDC)
         - Webhooks