message: Fix inconsistency with quoting
  Locally, the output looks like `'bar=...'`, but in CI the quotes are
  missing. Allow either.
diff: @@ -363,7 +363,7 @@ fn rebuilds_when_changing() {
  p.cargo("doc -v --no-deps -Zrustdoc-map")
  .masquerade_as_nightly_cargo()
  .with_stderr_contains(
  - "[RUNNING] `rustdoc [..]--extern-html-root-url 'bar=https://example.com/bar/1.0.0/[..]' [..]",
  + "[RUNNING] `rustdoc [..]--extern-html-root-url [..]bar=https://example.com/bar/1.0.0/[..]",
  )
  .run();
  }
  