[Proposal]: Null-conditional await

[CyrusNajmabadi]

• Proposal added: proposals/null-conditional-await.md
• Discussed in LDM
• Decision in LDM
• Finalized (done, rejected, inactive)
• Spec'ed

Discuss this proposal at: #8630

Design Meetings

https://github.com/dotnet/csharplang/blob/main/meetings/2022/LDM-2022-08-31.md#await