Missing RBI declarations for APIs made by `gobject-introspection`

[amomchilov]

TL;DR: tapioca dsl misses modules created for GObject interfaces, and maybe other types, too.

Cause

gobject-introspection is a gem brigding to GObject APIs.

For example, GObject interfaces get modelled via Ruby Modules, created here, and set via const_set here. Every such interface will have its const_source_location point to gobject-introspection/lib/gobject-introspection/loader.rb#L618.

When other gems (like gio2) import GObject interfaces, their const_source_location will always point to gobject-introspection/lib/gobject-introspection/loader.rb#L618. Since this location is outside the gem (and in gobject-introspection), Tapioca will skip those module, because it's not defined_in_gem?:

tapioca/lib/tapioca/gem/pipeline.rb

Lines 449 to 455 in b8161b8

	#: (String name, Module[top] constant) -> bool
	def skip_module?(name, constant)
	return true unless defined_in_gem?(constant, strict: false)
	return true if Tapioca::TypeVariableModule === constant
	false
	end

As a result, the generated gio2.rbi will be missing some interface declaration. It will still include lines that rely on them, leading to type errors.