Add `method` scope for functions invoked as members of an object

[atomiks]

TS and JS Grammar Extension version: 0.0.50 / latest

Similar to #700 but this should be possible without semantic colorization. Check if the function invocation was preceded by .

Example regexp implementation here: https://github.com/RunDevelopment/prism/blob/0685d641b000ff0ee5429001cdd439f2e05be882/components/prism-js-extras.js

example() // entity.name.function
obj.example() // entity.name.function.method