APIs which contain oblivious nullability should indicate that in Quick Info

[RikkiGibson]

Recently we made a change to give a heads up when interacting with nullable-oblivious variables:

It would be useful if this information were also conveyed when looking at a signature that contains oblivious nullability:

[MihuBot]

I'm a bot. Here are possible related and/or duplicate issues (I may be wrong):

• Mark calls to oblivious methods in #nullable contexts in Quick Info #41504
• Improving IDE experience around nullable-oblivious APIs #44063

[RikkiGibson]

Resolution to #41504 verifies that "is not nullable aware" is given on the return type, but, we don't do the same for the parameters.

It would be useful to know in both Quick Info and Signature Help, if a parameter is nullable oblivious, so that as a caller you can think about it and determine whether a possible null value is allowed to go in.

[jjonescz]

@CyrusNajmabadi, we talked about this offline and you said we should wait for more feedback - and here it is

[CyrusNajmabadi]

It's fine with me if someone wants to add thsi somehow.