Add Development.IDE.GHC.Error to the public API (#369)

And noSpan

ghcide.cabal

@@ -106,6 +106,7 @@ library
         Development.IDE.Core.RuleTypes
         Development.IDE.Core.Service
         Development.IDE.Core.Shake
+        Development.IDE.GHC.Error
         Development.IDE.GHC.Util
         Development.IDE.Import.DependencyInformation
         Development.IDE.LSP.LanguageServer
@@ -125,7 +126,6 @@ library
         Development.IDE.Core.FileExists
         Development.IDE.GHC.Compat
         Development.IDE.GHC.CPP
-        Development.IDE.GHC.Error
         Development.IDE.GHC.Orphans
         Development.IDE.GHC.Warnings
         Development.IDE.Import.FindImports

src/Development/IDE/GHC/Error.hs

@@ -17,6 +17,7 @@ module Development.IDE.GHC.Error
   , zeroSpan
   , realSpan
   , isInsideSrcSpan
+  , noSpan
 
   -- * utilities working with severities
   , toDSeverity