bootstrap: add change tracker entry

src/bootstrap/src/utils/change_tracker.rs

@@ -305,4 +305,9 @@ pub const CONFIG_CHANGE_HISTORY: &[ChangeInfo] = &[
         severity: ChangeSeverity::Info,
         summary: "`rust.llvm-tools` is now enabled by default when no `config.toml` is provided.",
     },
+    ChangeInfo {
+        change_id: 133068,
+        severity: ChangeSeverity::Warning,
+        summary: "Revert `rust.download-rustc` global default to `false` and only use `rust.download-rustc = \"if-unchanged\"` default for library and tools profile. As alt CI rustc is built without debug assertions, `rust.debug-assertions = true` will now inhibit downloading CI rustc.",
+    },
 ];