Fix warning description to show proper "sandboxed" value instead of "sandbox".

RELNOTES: None
PiperOrigin-RevId: 516184903
Change-Id: Idb7d9048aa3ece8679fbb6764a020eec74dfe392
diff --git a/src/main/java/com/google/devtools/build/lib/sandbox/SandboxModule.java b/src/main/java/com/google/devtools/build/lib/sandbox/SandboxModule.java
index 9a86962..53ebb06 100644
--- a/src/main/java/com/google/devtools/build/lib/sandbox/SandboxModule.java
+++ b/src/main/java/com/google/devtools/build/lib/sandbox/SandboxModule.java
@@ -514,7 +514,7 @@
                   String.format(
                       "%s uses implicit fallback from sandbox to local, which is deprecated"
                           + " because it is not hermetic. Prefer setting an explicit list of"
-                          + " strategies, e.g., --strategy=%s=sandbox,standalone",
+                          + " strategies, e.g., --strategy=%s=sandboxed,standalone",
                       spawn.getMnemonic(), spawn.getMnemonic())));
         }
       }