Updated integrated themes indent guide colors

[bgashler1]

Fixes #8410

[coveralls]

Coverage remained the same at 60.993% when pulling 26fd97b on bgashler1:bgashler1/issue/8410/indentation-guides-colors into 954e737 on Microsoft:master.

[sandy081]

@bgashler1 The primary TM setting we are using for indentation guides is guide and invisibles is the fall back if guide setting is not set. invisibles is mainly used for rendering white spaces color. So, changing invisibles will also impact white spaces color. If it is intentional, then we also need to change it for our default themes (Dark, Dark+, High Contrast)

Indentation Guides

• TM Setting : guide
• Selector: .lines-content .cigr

White spaces

• TM Setting : invisibles
• Selector: .token.whitespace

[sandy081]

Moving this to September milestone, since it is too late to make into August

[bgashler1]

@sandy081 does this look right?

[coveralls]

Coverage increased (+0.2%) to 61.186% when pulling 51c34e2 on bgashler1:bgashler1/issue/8410/indentation-guides-colors into 954e737 on Microsoft:master.

[sandy081]

@bgashler1 LGTM