message: Unify rustfmt.toml
  Summary: Copy `rustfml.toml` to `oss` folders.
diff: edition = "2018"
  -merge_derives = true
  +imports_granularity = "Crate"
  +merge_imports = true
  use_field_init_shorthand = true
  use_try_shorthand = true
  +
  +# We'd like to be this to be true, but...
  +# For long lines of derive, which are already merged, this will change
  +# where it indents it. That seems like a bug.
  +merge_derives = false
  