Add functions for slightly prettier (indented) formatting

[garyb]

@rintcius hacking this in should help with the codegen test stuff you're working on. With just these handful of changes our generated queries already look pretty close to that formatting we were applying by hand:

SELECT 
  c.c1 AS `Values of key a`, 
  c.c2 AS `Values of key id`, 
  c.c4 AS `Values of key id 2`, 
  c.c3 AS `Values of key value`
FROM
  ((SELECT 
    p5.g7 AS c1
  FROM
    (SELECT 
      `_sd_ensure_number`(r6.a) AS g7
    FROM
      `/datasource/dba83c92-955d-4bbd-8caa-0087c2e84413/ssssimple.ldjson` AS r6
    ) AS p5)
  UNION ALL
  (SELECT 
    p8.g10 AS c2, 
    p8.g12 AS c3, 
    p8.g11 AS c4
  FROM
    (SELECT 
      `_sd_ensure_number`(r9.entry.id) AS g10, 
      to_string(`_sd_ensure_number`(r9.entry.id)) AS g11, 
      `_sd_ensure_boolean`(r9.entry.value) AS g12
    FROM
      `/datasource/dba83c92-955d-4bbd-8caa-0087c2e84413/ssssst.ldjson` AS r9
    ) AS p8)
  ) AS c

[rintcius]

Great, thanks @garyb !