Add token background colors to themes

[mattmundell]

Add support for background colors to theme rules.

Closes #3429.

I did this before noticing #3429. Maybe helps someone wanting to patch their own version.

Example

id = 'patch'
tokenizer = {
  root: [
    [/^---\s.*/, "bredfill"],
    [/^\+\+\+\s.*/, "bredfill"],
    [/^\@\@\s.*/, "bredfill"],
    [/^-.*/, "minus"],
    [/^\+.*/, "plus"],
  ],
}

Mon.languages.register({ id: id,
                         firstLine: '^diff --git.*',
                         'mime-type': ['text/x-diff', 'text/x-patch', 'application/x-patch'],
                         extensions: ['.patch', '.diff'] })
Mon.languages.setMonarchTokensProvider(id, { tokenizer: tokenizer })

themeSolarized.rules.push({ "foreground": '073642',
                            "background": 'eee8d5',
                            "token": "bredfill" })

[mattmundell]

@microsoft-github-policy-service agree