Suppress legacy target framework build warnings and retarget tool projects to net10.0

[Copilot]

Several projects still target netcoreapp3.1 and net6.0 for compatibility, which now surfaces end-of-support and unsupported-TFM build warnings. This change keeps builds clean by suppressing those specific warnings in the remaining legacy-targeted projects, while retargeting the tool projects that no longer need net6.0 to net10.0.

• Scope

  • Applies only to projects that currently target out-of-support frameworks and emit these warnings during build.
  • Retargets tool projects that do not need legacy framework support.
  • Leaves unrelated warnings untouched.

• Project updates

  • Added CheckEolTargetFramework=false where SDK EOL warnings (NETSDK1138) were emitted for executable/test projects that still target legacy frameworks.
  • Added SuppressTfmSupportBuildWarnings=true where newer package dependencies emitted unsupported target framework warnings for netcoreapp3.1 / net6.0.
  • Changed Tools/HashTableSize and Tools/TrimVerification/BitFaster.Trimmed to target net10.0 instead of suppressing net6.0 build warnings.

• Where this was applied

  • Warning suppression:
    • BitFaster.Caching
    • BitFaster.Caching.UnitTests
    • BitFaster.Caching.UnitTests.Std
    • BitFaster.Caching.Benchmarks
  • Retargeted to net10.0:
    • Tools/HashTableSize
    • Tools/TrimVerification/BitFaster.Trimmed

• Implementation shape

  • Uses per-project, per-target-framework MSBuild properties for projects that still require legacy targeting.
  • Retargets standalone tool projects to net10.0 where legacy targeting is unnecessary.

<PropertyGroup Condition="'$(TargetFramework)' == 'net6.0'">
  <CheckEolTargetFramework>false</CheckEolTargetFramework>
  <SuppressTfmSupportBuildWarnings>true</SuppressTfmSupportBuildWarnings>
</PropertyGroup>

<PropertyGroup>
  <TargetFramework>net10.0</TargetFramework>
</PropertyGroup>

[bitfaster]

@copilot change this project and BitFaster.Trimmed.csproj to target net10.0 instead of suppressing the build warning.

[Copilot]

Updated both tooling projects to target net10.0 in 06c3f09.

[coveralls]

coverage: 99.21%. remained the same — copilot/suppress-build-warnings-net-versions into main