Remove unused method
Bring IBaseInfo#deprecated? under test
Simplify method
Make GValue#set_value return nil

This matches the return value of the specialized #get_<type> methods.
Make GObject::Value#value= an alias of #set_value
Remove unused methods from UnintrospectableTypeInfo
Remove unused methods from FieldBuilder
Use GObject::Object#is_floating directly
Remove unused object ref methods
Bring ITypeInfo#name under test
Bring #type_name under test
Add skip guard
Increase coverage [merges 'increase-coverage']
Explain RuboCop style choices
Disable TrailingComma cop
Improve RuboCop configuration [merges 'rubocop-configuration']
Don't needlessly add _ to list of parameter names
Avoid use of an ignored dummy argument altogether
Unify implementation of #instantiate_class
Make test:suites task pass again