Fix typo in namespace casing for PgSql\Connection

Corrected the capitalization of the "PgSql" namespace in the `pg_set_chunked_rows_size` function definition. Ensures consistency with PHP's standard naming conventions and avoids potential issues with autoloading or referencing.

pgsql/pgsql.php

@@ -2119,7 +2119,7 @@ function pg_socket_poll($socket, int $read, int $write, int $timeout = -1): int
 /**
  * @since  8.4
  */
-function pg_set_chunked_rows_size(Pgsql\Connection $connection, int $size): bool {}
+function pg_set_chunked_rows_size(PgSql\Connection $connection, int $size): bool {}
 /**
  * @since 8.4
  */