prelude: Bump to 1.0-rc1 frozen

Author: jrtc27

prelude.adoc

@@ -16,8 +16,8 @@
 // as frozen can still change in incompatible ways) as we cannot break ABI once
 // features are implemented in toolchains. Similarly stable is still frozen
 // just by another name for policy reasons.
-:revlifecycle: stable
-:revnumber: 0.9.1
+:revlifecycle: frozen
+:revnumber: 1.0-rc1
 ifeval::["{revlifecycle}" == "dev"]
 :revdate: {date}
 :revremark: Pre-release