Update document to include benchmark CLI command (#2314)

## Update document to include benchmark CLI command

## Checklist before requesting a review
- [ ] Add unit tests for this change.
- [ ] Make sure all tests can pass.
- [ ] Update documents if necessary.
- [ ] Lint and apply fixes to your code by running `lintrunner -a`
- [ ] Is this a user-facing change? If yes, give a description of this
change to be included in the release notes.

## (Optional) Issue link

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
 ======================