distinguish between object literal and other properties

[Martin Aeschlimann]

In the TypeScript TextMate grammar, object literals get the scope meta.object-literal.key.ts and class interface properties get variable.object.property.

const x = { prop1: 1 }
interface X { prop2: 1 }

Semantic token don't distinguish between the two.
Some themes use the different scopes to colorize differently what causes in less colors when enabling semantic highlighting.

We could add a subtype 'objectProperty` to enable specific themeing.