Update document to include benchmark CLI command

Author: shaahji

docs/source/reference/cli.rst

@@ -1,5 +1,5 @@
 Command Line Tools
-===================
+==================
 
 Olive provides command line tools that can be invoked using the ``olive`` command.
 
@@ -81,7 +81,7 @@ Automatically optimize the input model for the given target and precision.
     :path: auto-opt
 
 Generate Adapters
-==================
+=================
 
 Generate ONNX model with adapters as inputs.
 
@@ -138,7 +138,7 @@ Configure Qualcomm SDK.
     :path: configure-qualcomm-sdk
 
 Shared Cache
-=============
+============
 
 Delete Olive model cache stored in the cloud.
 
@@ -148,6 +148,17 @@ Delete Olive model cache stored in the cloud.
     :prog: olive
     :path: shared-cache
 
+Benchmark
+=========
+
+Run benchmarking using llm-eval.
+
+.. argparse::
+    :module: olive.cli.launcher
+    :func: get_cli_parser
+    :prog: olive
+    :path: benchmark
+
 Providing Input Models
 ======================