- At the moment, `delete_all` doesn't support `WITH`,
  `WITH RECURSIVE` and `DISTINCT` statement.

  Calling `Post.with(ex: Post.where(title: "")).delete_all`
  raises an error.
  However calling `Post.with(ex: Post.where(title: "")).update_all`
  executes the following SQL `UPDATE "posts" SET "title" = blabla`,
  which can be surprising for users.

  This commit adds a deprecation message to warn users
  that those statements have no effect, with the intention of
  raising the same error as when using `delete_all` in a future
  Rails release.