feat: Include symbols in NuGet package

[rhysparry]

This pull request includes updates to the Dirt.Args project file to enhance debugging and diagnostics capabilities.

Enhancements to debugging and diagnostics:

• Dirt.Args/Dirt.Args.csproj: Added properties to include symbols and specify the symbol package format as snupkg to improve debugging and diagnostics.

[rhysparry]

This change is part of the following stack:

• feat: Include symbols in NuGet package #28 ◀

_{Change managed by git-spice.}