[Misc] Fix typo (vllm-project#18330)

Signed-off-by: Yuqi Zhang <yuqizhang@google.com>

Author: Unprincess17

examples/lmcache/disagg_prefill_lmcache_v1/disagg_vllm_launcher.sh

@@ -54,6 +54,6 @@ elif [[ $1 == "decoder" ]]; then
 
 else
     echo "Invalid role: $1"
-    echo "Should be either prefill, decode"
+    echo "Should be either prefiller, decoder"
     exit 1
 fi