Add the regex language parser for JSON

[daxian-dbw]

• Add a regex parser for JSON, to generate tokens for keys, strings, numbers, and constants of a Json code block.
• Removed the json alias from the JavaScript language parser.

Before this change

Keys and value strings are NOT differentiated, and number is not highlighted:

After the change

Keys and value strings are differentiated, and number is highlighted:

Dark theme screenshot:

Light theme screenshot:

[daxian-dbw]

@michael-hawker gentle ping :) Can you please review this PR? Thanks!

[michael-hawker]

@niels9001 any thoughts on the coloring scheme. @daxian-dbw were these picked to match an existing editor, arbitrarily, or from some guidance somewhere?

[daxian-dbw]

It's sort of picked with the reference of how JSON code block is displayed in bat and glow:

I chose to use the same color as bat for JSON keys, but the color used for string value in bat doesn't look good in white background. bat doesn't differentiate JSON constant from numbers, so I borrowed the number color used in glow for that.

bat

glow

[daxian-dbw]

Thanks for the review!