Future annotations

[vemel]

Highlights

• All packages use new syntax for type annotations

Added

• [services] Support future type annotations in all generated files
• [services] type: ignore comments always have a specific type

Changed

• [services] All generated modules use __future__.annotations
• [services] Subscripts are no longer stringified
• [services] Subresources are sorted alphabetically, removed pseudo-topological sorting
• [services] Replaced Optional[...] with ... | None
• [services] Replaced inline Union with a new X | Y syntax (named Unions preserve old style for python<3.10 compatibility)
• [services] Replaced typing.Dict/List/type with builtins equivalients
• [services] Replaced typing.Set with builtins.set (currently unused in botocore)
• [aio-services] Importing <service>.service_resourse is no longer safe when boto3 and aioboto3 are not installed
• [all] All annotations synced from static stubs

Fixed

• [services] Docstring headers for generated files were not formatted properly
• [builder] Unnamed Union returns correct required imports for rendering
• [services] BotocoreClientError is no longer generated, using botocore.exceptions.ClientError instead
• [services] Client.close method is not longer generated, inherited from static stubs instead
• [services] Client.exceptions is inherited from BaseClientExceptions
• [services] Conditional imports marked with # type: ignore[assignment] for better mypy support