Add Vivid vs. Bold difference to README

[ecbrodie]

What is the difference between Bold, Vivid, and regular One Dark Pro?

I wish I did not have to ask this question, that it was just available in the README. I think it will be worthwhile to add a small blurb about this to the README.

[GorvGoyl]

my guess it's a subtle difference b/w versions. I tried switching the theme for below inline code public void onCreate(Bundle savedInstanceState)

default theme: base theme. Bold: some keywords become bold for ex: onCreate becomes bold, colors are same. Vivid: all colors become a bit brighter.. very subtle difference. rest is same, no boldness.

So, I'm going with Bold.. gives additional visual cue to keyword.