Idea for Collection Literals

[Izz Rainy]

Hello! Hopefully this is the right place for this suggestion - if it isn't,
please let me know.

Recently, I've read some of the discussion linked in JEP 269 (Convenience
Factory Methods for Collections), including why Collection Literals were
shelved when brought up in Project Coin and Lambda. I believe that things
may be different enough now (with dynamic constants possible, local
variable inference and lambdas present, value types closer to completion,
and project Amber bringing "smaller" features under consideration) to bring
them up yet again.

I've tried writing an informal proposal for them that tries to answer the
main questions brought up in those original discussions:
https://gist.github.com/l-Luna/08b6574d0c840de93634cf8d1e43c494

It tries to stay general to multiple kinds of collections (so long as they
are either "list like" or "map like"), without trying to be too open ended,
and includes ways of clearly specifying the target type and mutability,
while also trying to infer a reasonable default for both.

I understand that it's still unlikely to be added in the near future, but
thought it wouldn't hurt to bring up again.