Release 9.0.0-pre.20250402.1 (2025-04-09)

Baseline: 37f66573

Important changes:

  - The `config` command now reports which configurations have had
    the test configuration trimmed.
  - Stop documenting the vestigial `distribs` attribute.

This release contains contributions from many people at Google, as well as Alberto Cavalcante, Fabian Meumertzheim, Farid Zakaria.