refactor(references.lua): move pipe chain column resolution logic before target definition check

[PMassicotte]

Small bug fix when using renaming symbol in a pipe expression.

summarise_mtcars <- function(data = mtcars) {
  data |>
    as_tibble(rownames = "model") |>
    mutate(power_to_weight = hp / wt) |>
    summarise(
      mean_mpg = mean(mpg),
      mean_p2w = mean(power_to_weight),
      .by = cyl
    )
}

Place the cursor on power_to_weight in the mutate() function. Try to rename, and only the power_to_weight in the summarise() gets renamed. This PR make sure that both are renamed.

[jalvesaq]

Thank you! I confirm the bug and that the pull request fixes it!