fix: fix uint and string types

[josedonizetti]

Fix the types, because uint32 was generating a name Uint32, I we should match the wrappers and be UInt32.

Also for string, I've renamed it to str because string there is a conflict with the naming, if we use string it generates a value of String_ with a getter GetString_(), the underscore is really weird, so I've change it to str, let me know what you think.