Update mangling rules

[vdka]

File mangling

The file the compiler was invoked upon (known as the invocation file) has no mangle prefix for it's top level entities

Every other file is mangled with it's path relative to the invocation file.
eg:
main.kai (invocation file)

#import "math.kai"
// mangled: `main`
main :: fn() -> void {...}

math.kai

mangled: `math.lerp`
lerp :: fn() -> void {...}

Function Scopes

Function scopes only mangle compile time entities and anonymous functions.
eg:

main :: fn() -> void {
    // mangled name = `main.map`
    sort :: fn(in: []int, predicate: (int, int) -> bool) -> void { ... }
    // param #2's anon func would mangle too `.fn` (prefix is ditched)
    sort(myArray, fn(x, y: int) -> bool { ... })
}

Type Scopes

Type Scopes mangle their entities using the current scope prefix + the name of the type.
eg:

Person :: struct {
    firstName, lastName: string
    // mangled name = `Person.new`
    new :: fn(first, last: string) -> void { ... }
}