fix:linq collections contain in C# 14

[StellaAlexis]

When updating my project to .Net 10 and C# 14 I noticed that the linq collection expressions around contains were broken.
References on the change in C#14 can be foundhere

To validate the issue I changed the TargetFramework and LangVersion of LinqTests.csproj. That resulted in a bunch of the existing tests failing right away.
Suggesting a fix similar to how EnumerableContains is written. After the change all Linq tests are passing again.

[jeremydmiller]

@StellaAlexis Can you add tests for this?

[StellaAlexis]

@StellaAlexis Can you add tests for this?

@jeremydmiller what kind of additional tests do you want to see?
I figured reusing the test suite in place would be sufficient as in the master branch there are already 44 failures on the LinqTests. They just weren't flagged by the update to .net 10 as the project was hardcoded to C# 13.
The PR fixes all of the following failures.

[StellaAlexis]

Noticed the failing tests. Assume that is because of the hardcoded .net 10 framework. Managed to also run the tests without it so removed that part.

[1sabelle]

We're also affected by this. Temporary solution for us is to pin language version to C# 13 just as seems to have been the prior solution here. Nice to see a fix.

[Hawxy]

I've updated linqtests to test against each langversion we support, so we can catch any ongoing issues in this space. This should be good to go in.

[jeremydmiller]

Thanks @Hawxy !