fix handling of one-element arrays in doc code generator #1911

Job	Run time
compile_and_lint	1m 52s
test (postgres, postgres, postgres://root:[email protected]/sqlpage)	2m 13s
test (mssql, mssql, mssql://root:[email protected]/sqlpage)	1m 49s
test (mysql, mysql, mysql://root:[email protected]/sqlpage)	2m 13s
test (odbc, postgres, Driver=PostgreSQL Unicode;Server=127.0.0.1;Port=5432;Database=sqlpage;UID=r...	2m 42s
windows_test	5m 37s
docker_build (linux/amd64)	4m 51s
docker_build (linux/arm/v7)	4m 56s
docker_build (linux/arm64)	5m 20s
docker_push	28s
	32m 1s

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