Need to fix trailing line break in `dracula.rstheme`

[mjsteinbaugh]

Currently seeing this warning when loading the theme directly from dracula.rstheme:

Warning in readLines(themeFile, encoding = "UTF-8") :
  incomplete final line found on '~/Desktop/Dracula-RStudio/dracula.rstheme'
Calls: <Anonymous> -> readLines

[mjsteinbaugh]

I can file a pull request for this, but a trailing line break simply needs to be added to the file.

[mjsteinbaugh]

Theme looks great by the way!