fix(go): properties on interfaces should be uppercased

[DanielMSchmidt]

I'm trying to adjust rosetta so that it aligns with what JSII is doing. I am seeing consistently lower-cased property / method names, where JSII would uppercase them. One example from the cdktf aws pre-built provider is this interface in TS and the coresponding go struct. Rosetta would lower-case the names the JSII puts in uppercase.

[comcalvi]

I see what this is doing but I'm not convinced that this is the right solution yet.

Since rosetta is lower casing things that should be upper cased, and given that in Go every upper case variable is automatically exported, the context's isExported must be wrongly set to false somewhere. This fix decides to ignore the current isExported value entirely, and instead go by isPublic; but that doesn't seem right because public in TS and export in TS are not the same thing. export is needed to make something publicly accessible, public alone is not sufficient, so ignoring it here feels wrong.

The only time we want to make these interface properties capitalized is when we have an exported interface, like this:

export interface IFoo {
  readonly foo: string;
}

Given that this bug is happening because the current context's isExported is wrongly set to false, when this code processes foo the previous context's isExported must be already false. The previous context is from the previous node, which must be the IFoo here. IFoo is exported, so how is the previous context false? Can you figure out why that's happening?