Fix the generated C# code for plain properties:
- Value types should not be initialized with `= null!`
- Arrays and maps should be `List<T>` and `Dictionary<string, TValue>`
* Remove leading and trailing whitespace in resource properties
* Make tests pass
* Add PULUMI_ACCEPT support to docs gen tests
* Handle a couple more places
Co-authored-by: Pat Gavlin <pat@pulumi.com>
These changes fix a regression introduced by #6686 that caused the SDK
code generators for .NET, Python, and Typescript to omit definitions for
plain object types. This regression occurred because #6686 drew a
clearer line between types used as resource arguments and types used
as function arguments, but conflated "resource arguments" with "inputty
types". This caused the code generators to generate inputty types for
any types used as resource arguments, even those that are used for
plainly-typed properties.
Fixes#6796.
