update debug flag

Author: Jay2113

src/pages/[platform]/reference/cli-commands/index.mdx

@@ -55,7 +55,7 @@ Sandbox enables you to develop your backend alongside your frontend's developmen
 
 ### Options
 
-- `debug` (_boolean_) - Print debug logs to the console (default: false)
+- `--debug` (_boolean_) - Print debug logs to the console (default: false)
 - `--dir-to-watch` (_string_) - Directory to watch for file changes. All subdirectories and files will be included. Defaults to the amplify directory.
 - `--exclude` (_string[]_) - An array of paths or glob patterns to ignore. Paths can be relative or absolute and can either be files or directories.
 - `--identifier` (_string_) - An optional name to distinguish between different sandbox environments. Default is the name of the system user executing the process