Highlight previous user input (#2507)

Co-authored-by: Allen Hutchison <adh@google.com>

packages/cli/src/ui/components/messages/UserMessage.tsx

@@ -17,7 +17,15 @@ export const UserMessage: React.FC<UserMessageProps> = ({ text }) => {
   const prefixWidth = prefix.length;
 
   return (
-    <Box flexDirection="row" marginY={1}>
+    <Box
+      borderStyle="round"
+      borderColor={Colors.Gray}
+      flexDirection="row"
+      paddingX={2}
+      paddingY={0}
+      marginY={1}
+      alignSelf="flex-start"
+    >
       <Box width={prefixWidth}>
         <Text color={Colors.Gray}>{prefix}</Text>
       </Box>