doc: update usage

Author: MrMarble

README.md

@@ -1,4 +1,4 @@
-# ZMK Layout viewer
+# ZMK viewer
 
 ![GitHub go.mod Go version](https://img.shields.io/github/go-mod/go-version/mrmarble/zmk-layout-viewer)
 [![Vuln](https://github.com/MrMarble/zmk-layout-viewer/actions/workflows/vuln.yml/badge.svg)](https://github.com/MrMarble/zmk-layout-viewer/actions/workflows/vuln.yml)
@@ -9,36 +9,39 @@ A **work in progress** Cli tool to generate preview images from a zmk .keymap fi
 ## Usage
 
 ```shell
-Usage: zmk-layout-viewer <keyboard>
+Usage: zmk-viewer generate <keyboard-name>
+
+Generate layout image.
 
 Arguments:
-  <keyboard>    Keyboard name to fetch layout.
+  <keyboard-name>    Keyboard name to fetch layout.
 
 Flags:
   -h, --help           Show context-sensitive help.
+  -D, --debug          Enable debug mode
+
   -f, --file=STRING    ZMK .keymap file
   -t, --transparent    Use a transparent background.
   -o, --output="."     Output directory.
-      --debug          Enable debug logging.
 ```
 
 Keyboard name should be the same as in https://config.qmk.fm.
 
 ```shell
-zmk-layout-viewer cradio
+zmk-viewer generate cradio
 ```
 Will output this image:
 
 ![](assets/layout.png)
 
-You can pass a .keymap file ([this one for reference](https://github.com/MrMarble/zmk-config/blob/master/config/cradio.keymap)) to generate the layout with bindings
+You can pass a .keymap file ([this one for reference](https://github.com/zmkfirmware/zmk/blob/main/app/boards/shields/cradio/cradio.keymap)) to generate the layout with bindings
 
 ```shell
-zmk-layout-viewer -f ~/zmk-config/config/cradio.keymap cradio
+zmk-viewer generate -f ~/zmk-config/config/cradio.keymap cradio
 ```
 will output an image for each layer:
 
-![](assets/default_layer.png)
-![](assets/left_layer.png)
-![](assets/right_layer.png)
-![](assets/tri_layer.png)
+![](assets/cradio_default_layer.png)
+![](assets/cradio_left_layer.png)
+![](assets/cradio_right_layer.png)
+![](assets/cradio_tri_layer.png)