updated projects to dotnet9 + switched to incremental source generator

[MaximTkachenko]

No description provided.

[MaximTkachenko]

• fix warnings
• improve the code quality
• start benchmarks again

[Copilot]

Pull Request Overview

Updates the solution to target .NET 9 and migrates the source generator from the classic ISourceGenerator model to an incremental IIncrementalGenerator while updating Roslyn and test/benchmark dependencies.

• Upgrade target frameworks (net5.0 -> net9.0) and dependency versions across projects
• Introduce incremental source generator pipeline and supporting launchSettings for debugging
• Adjust tests to instantiate the generated parser directly

Reviewed Changes

Copilot reviewed 8 out of 9 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
test/Parsers.Tests.csproj	Upgrades test project to .NET 9 and updates test dependencies.
test/ParserGeneratorTests.cs	Replaces reflective instantiation with direct construction of generated parser.
src/Parsers/Parsers.csproj	Upgrades runtime parser project framework and Roslyn dependency.
src/Parsers.SourceGenerator/Properties/launchSettings.json	Adds launch profile for debugging the source generator.
src/Parsers.SourceGenerator/Parsers.SourceGenerator.csproj	Updates analyzer/compiler packages and enables incremental generator-related build properties.
src/Parsers.SourceGenerator/ParserSourceGenerator.cs	Reimplements generator as an incremental generator and refactors symbol discovery logic.
benchmark/Parsers.Benchmarks.csproj	Upgrades benchmark project to .NET 9 and newer BenchmarkDotNet.
.github/workflows/dotnet.yml	CI updated to use .NET 9 SDK.

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