docs: corrections to how to use help

Co-authored-by: ZHANG Yuntian <[email protected]>

docs/tutorials/usage.md

@@ -6,7 +6,7 @@ After typing `rsdk` into your terminal, if there is no subcommand suggestion aft
 
 From there, you can use autocompletion to query the supported command list.
 
-Running `rsdk help` command will display its help text.
+Running a command with `--help` argument will display its help text.
 
 # Use TUI