add comment and clean up

Author: majocha

src/Compiler/Facilities/DiagnosticsLogger.fs

@@ -909,6 +909,8 @@ type StackGuard(maxDepth: int, name: string) =
     static member GetDepthOption(name: string) =
         GetEnvInteger ("FSHARP_" + name + "StackGuardDepth") StackGuard.DefaultDepth
 
+// UseMultipleDiagnosticLoggers in ParseAndCheckProject.fs provides similar functionality.
+// We should probably adapt and reuse that code.
 module MultipleDiagnosticsLoggers =
     let Parallel computations =
         let computationsWithLoggers, diagnosticsReady =

tests/FSharp.Compiler.UnitTests/BuildGraphTests.fs

@@ -11,7 +11,6 @@ open FSharp.Compiler.BuildGraph
 open FSharp.Compiler.DiagnosticsLogger
 open Internal.Utilities.Library
 open FSharp.Compiler.Diagnostics
-open FSharp.Compiler.Tokenization.FSharpTokenTag
 
 module BuildGraphTests =