updated optimize/prefetch properties

Author: ericd-mst-github

articles/virtual-machines/linux/image-builder-json.md

@@ -1163,13 +1163,9 @@ The `optimize` property can be enabled while creating a VM image and allows VM o
 
 ```json
 "optimize": { 
-
       "vmboot": { 
-
         "state": "Enabled" 
-
       } 
-
     }
 ```
 
@@ -1184,6 +1180,8 @@ optimize: {
 ```
 ---
 
+- **vmboot**: A configuration related to the booting process of the virtual machine (VM), used to control optimizations that can improve boot time or other performance aspects.
+- **state**: The state of the boot optimization feature within `vmboot`, with the value `Enabled` indicating that the feature is turned on to improve image creation time.
 
 ## Properties: source