Fix missing :: prefix on T::Boolean, T::Class, and T::Module in to_rbi

[Morriar]

Summary

• Boolean#to_rbi, Class#to_rbi, and Module#to_rbi were returning T::Boolean, T::Class[...], and T::Module[...] without the :: prefix
• All other to_rbi methods already correctly used fully qualified names (e.g., ::T.anything, ::T.nilable(...), ::T.proc)
• Fixed all three to return ::T::Boolean, ::T::Class[...], and ::T::Module[...]

Test plan

• Updated test expectations in type_test.rb to match the new output
• All 497 tests pass

[Morriar]

cc @jesse-shopify

[jesse-shopify]

Great! This will fix the errors I ran into.