chore: import upstream snapshot with attribution

testing/generation/command_docs/synopses/create_publication.txt

@@ -0,0 +1,9 @@
+CREATE PUBLICATION $name$
+    [ FOR ALL TABLES
+    | FOR $publication_object$ [ , ... ] ]
+    [ WITH ( { $publication_parameter$ [ = $value$ ] } [ , ... ] ) ]
+
+where $publication_object$ is:
+
+{ TABLE { ONLY $table_name$ | $table_name$ [ * ] } [ ( $column_name$ [ , ... ] ) ] [ WHERE ( $expression$ ) ] } [ , ... ] |
+    TABLES IN SCHEMA { $schema_name$ | CURRENT_SCHEMA } [ , ... ]