Adding hyphen to command-line arguments

Co-authored-by: Amy Reeve <amy.reeve@unity3d.com>

Author: noellie-velez

com.unity.netcode.gameobjects/Documentation~/command-line-arguments.md

@@ -2,7 +2,7 @@
 
 Use [command-line arguments](https://docs.unity3d.com/Documentation/Manual/CommandLineArguments.html) to configure certain aspects of your game at launch. This is especially useful for dedicated server builds, where arguments let you override default network settings such as the IP address and port.
 
-## Using Command Line Arguments
+## Using command-line arguments
 
 When launching a standalone build (for example, a headless dedicated server), you can supply custom arguments to modify runtime behavior.