title: Use Roslyn code analyzer in same solution
body: <p>I have a solution comprised of several .NET Core projects.  I have a few code analysis tasks I'd like to perform that are only applicable to this solution, so it doesn't make sense to put them in a separate repo/solution.  Using the appropriate template, I've created three projects for the analyzers:</p>
  
  <ul>
  <li>Example.Analyzer</li>
  <li>Example.Analyzer.Test</li>
  <li>Example.Analyzer.Vsix</li>
  </ul>
  
  <p>Example.Analyzer.Vsix doesn't compile because Visual Studio requires .NET Framework, but I'm targeting .NET Core for cross-platform use.  For now, I'm ignoring that project, but I intend to delete it.  Example.Analyzer and Example.Analyzer.Test both target netcoreapp3.0, along with all the other projects in the solution.</p>
  
  <p>I've written my analyzers and the tests pass.  However, I'm not sure how to actually use these analyzers from the other projects.  I've tried adding Example.Analyzer as a dependency via a ProjectReference, but that doesn't seem to enable the analyzers.</p>