Make JSON colors more contrast

[flaksp]

Current colors are too smooth and not contrast. It's hard to read huge JSONs.

My suggestions:

• rgba(0,0,0,.87) - for property names (Google recommends that color for black text on pure white backgrounds)
• #0B7500 - for strings.
• #1A01CC - for numbers and nulls.

This color scheme is similar to JSON Formatter.

This is how it will look like:

[flaksp]

Probably at high-contrast and expensive displays current colors look good, but at cheap models (as my current) it looks unreadable.