upgrade net10

[ryanheath]

This pull request focuses on modernizing and simplifying the codebase, primarily through code style improvements, C# language feature adoption, and minor dependency updates. The changes include converting namespaces to file-scoped declarations, using expression-bodied members for concise code, updating project configuration to leverage the latest C# features, and upgrading a test SDK dependency.

Codebase modernization and simplification:

• Converted namespaces to file-scoped declarations and removed unnecessary braces for improved readability across multiple files, such as NodaTimeField.cs, CustomQueryTranslators.cs, CustomQueryValueConverters.cs, Extensions.cs, and several files under Imports/NodaTime.Serialization.JsonNet. [1] [2] [3] [4] [5] [6] [7] [8] [9]

• Replaced method bodies with expression-bodied members for simple methods and properties to reduce boilerplate and improve clarity, especially in utility and converter classes. [1] [2] [3] [4] [5] [6] [7]

• Used modern C# language features such as pattern matching (is not), null-coalescing assignment, and null-conditional operators to simplify logic and improve code safety. [1] [2] [3] [4]

Project configuration updates:

• Enabled latest C# language version and implicit usings in Directory.Build.props to support modern syntax and reduce manual using directives.

• Updated Microsoft.NET.Test.Sdk package to version 18.0.1 for improved test infrastructure.