Quote package; added newline at end of file

inst/templates/vis_object.Rmd

@@ -3,9 +3,10 @@
 <!-- Component created on <% timestamp %> -->
 
 ```{r}
-if (!requireNamespace(<% package %>, quietly = TRUE)) {
+if (!requireNamespace("<% package %>", quietly = TRUE)) {
     stop('The package <% package %> is needed to embed objects of class <% class %>.', call. = FALSE)
 }
 
 readRDS('envs/<% component_id %>.rds')
 ```
+