Support for square bracket parameters in scripted_effects and scripted_triggers

Hey, would it be possible to add support for square bracket parameters? The way they work is if paramater in bracket is passed, the rest of racket is executed. The dollar and bracket parameters can overlap. I could try make change but never used F#

```
#Province effect
upgrade_building = {
[[trade]
if = {
limit = { has_building = trade_depot }
add_building = stock_exchange
}
else_if = {
limit = { has_building = marketplace }
add_building = trade_depot
}
]
[[government]
if = {
limit = { has_building = courthouse }
add_building = town_hall
}
]
}

upgrade_building = { trade = yes }
```

```
define_advisor_of_random_type = {
define_advisor = {
[[name] name = $name$ ]
type = treasurer
skill = $skill$
[[culture] culture = $culture$ ]
[[religion] religion = $religion$ ]
[[discount] discount = $discount$ ]
[[cost_multiplier] cost_multiplier = $cost_multiplier$ ]
}
}

define_advisor_of_random_type = { skill = 1 culture = some_culture }
```