[DCR]: Improve NU5128 warning text

[anangaur]

NuGet Product(s) Affected

NuGet.exe, MSBuild.exe, dotnet.exe

Current Behavior

Customer reported the following:

The solution was even simpler:

<PropertyGroup>
    <TargetFramework>netstandard2.0</TargetFramework>
    <LangVersion>latest</LangVersion>
    <Nullable>enable</Nullable>
    <IsRoslynComponent>true</IsRoslynComponent>
    <NoWarn>NU5128</NoWarn>
</PropertyGroup>

Anyway, since you planned not to "fix" this, it would be nicer to add to the warning message that it can be safely ignored when packaging an analyzer.

---

I created a C# code generator which is effectively an analyzer, so there is no binary to "deploy".

Upon compiling with pack, NuGet complains with those two warnings:
warning NU5128: Some target frameworks declared in the dependencies group of the nuspec and the lib/ref folder do not have exact matches in the other location. Consult the list of actions below:
warning NU5128: - Add lib or ref assemblies for the netstandard2.0 target framework

I read these are well-known false positives in analyzer projects.
Anyway, they are annoying. Does anyone know how can I get rid of them? I am trying not to take any drastic action like "-NoPackageAnalysis"
Note: I am have no "nuspec" but all the nuget info are inside the csproj.

Desired Behavior

Add additional text to the warning message indicating this can be suppressed while packing a analyzer.

Additional Context

No response