chore: remove backticks and resolve linting issues

Signed-off-by: Alano Terblanche <18033717+Benehiko@users.noreply.github.com>

cli/command/image/prune.go

@@ -75,7 +75,7 @@ func runPrune(ctx context.Context, dockerCli command.Cli, options pruneOptions)
 			return 0, "", err
 		}
 		if !r {
-			return 0, "", errdefs.Cancelled(errors.New("`image prune` has been cancelled"))
+			return 0, "", errdefs.Cancelled(errors.New("image prune has been cancelled"))
 		}
 	}