Use 'new' expression in places where the type is evident for content (#2590)

* Content.Client

* Content.Benchmarks

* Content.IntegrationTests

* Content.Server

* Content.Server.Database

* Content.Shared

* Content.Tests

* Merge fixes

Co-authored-by: metalgearsloth <31366439+metalgearsloth@users.noreply.github.com>

Content.Shared/Chemistry/Solution.cs

@@ -17,7 +17,7 @@ namespace Content.Shared.Chemistry
     {
         // Most objects on the station hold only 1 or 2 reagents
         [ViewVariables]
-        private List<ReagentQuantity> _contents = new List<ReagentQuantity>(2);
+        private List<ReagentQuantity> _contents = new(2);
 
         public IReadOnlyList<ReagentQuantity> Contents => _contents;