message: Improve rollup text by stating that we should be careful about what we include
diff: @@ -22,8 +22,19 @@ queue has been merged.
  ## Making a Rollup
  -1. Using the interface on [Homu queue], select a few pull requests and then use
  - "rollup" button to make one. (The text about fairness can be ignored.)
  +1. Using the interface on [Homu queue], select pull requests and then
  + use "rollup" button to make a rollup pull request. (The text about
  + fairness can be ignored.)
  + **Important note**: consider for addition PRs marked as
  + `rollup=always`, `rollup=maybe` and `rollup=iffy`, based on the
  + review policies of [the Rollups section]. Be extra careful when
  + deciding what to include, in particular on `rollup=maybe` and
  + `rollup=iffy` PRs. We should try as much as possible to avoid risking
  + and hit regressions (bugs or perf). Also consider that contributors
  + often forget to tag things with rollup=never, when they should have
  + done so, so when PRs are not explicitly tagged with rollup, be extra
  + careful.
  +
  2. Run the following command in the pull request thread:
  ```
  