Update src/app/server-cluster/ServerClusterInterface.h

Co-authored-by: Boris Zbarsky <bzbarsky@apple.com>

Author: andy31415

src/app/server-cluster/ServerClusterInterface.h

@@ -45,7 +45,7 @@ class ServerClusterInterface
 
     /// Starts up the server cluster interface.
     ///
-    /// The `context` lifetime is guaranteed to be valid
+    /// The `context` lifetime must be guaranteed to last
     /// until `Shutdown` is called.
     virtual CHIP_ERROR Startup(ServerClusterContext * context) = 0;