With expression

[wise0704]

https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/operators/with-expression

Syntax is identical to:

• LHS: switch expression (?<!\.)\b
• RHS: anonymous object b\s*(?=\{|$) + #initializer-expression + (?<=\})
• context & op. precedence: switch expression

I chose keyword.other.with.cs as it seemed most appropriate, but let me know if there's a better name for it.

Related: #239

[JoeRobich]

The change looks great. Thanks @wise0704!

[wise0704]

Seems like both new { } and with { } fail when the line ends with a comment before { on the next line:

var a = new // this will not match
{ ... };
var b = a with // so this one won't either
{ ... };

Should I just fix both in this PR? I guess changing the lookahead to (?=\{|//|/*|$) should fix it.

[JoeRobich]

Should I just fix both in this PR?

Since this was a pre-existing issue, we can take the fix separately.