Enable color for active indent guide, also adjust whitespace + inactive indent color

[smt923]

This PR will enable (there doesn't appear to be an editor setting for it, just a color) the new active indent guide color

While I was there I brought the whitespace & now 'inactive' indent guide colors just a little bluer towards the dracula theme, as they didn't have a color before - if this isn't liked/desired I can make a new PR for just the active indent color, but it's not a drastic change and I think it fits in with the theme a little better than how it was before, where it was a little too grey-ish

Before w/ whitespace

After w/ whitespace

Before w/o whitespace

After w/o whitespace

Will close #73

(edited images after new commit)

[dsifford]

Thanks for the contribution.

Have a look at my comments and let me know what you think.

[dsifford]

Can we try #424450 for whitespace and see what that looks like?

Reason being: I'd like to keep as closely uniform as I can to dracula/vim.

Also, the C8 part to my knowledge shouldn't do anything here. The extended 2 digits of the hex values accounts for alpha and that needs to be 00-99 inclusive.

[dsifford]

Also, can we call this NonText rather than Whitespace to stay uniform with the vim terminology?

[smt923]

👍 Makes sense to stick to the vim theme, and it looks good to me, pushing shortly

[smt923]

Pushed the changes and updated the after images too

[dsifford]

LGTM. Thanks!