Add file names to verbose output (#9)

Author: kevinmbeaulieu

Sources/SwiftTypeAdoptionReporter/FastStrategy.swift

@@ -42,6 +42,18 @@ public class FastStrategy: Strategy {
                 usageCount: usageCounts[type] ?? 0
             )
         }
+
+        if verbose {
+            for type in types {
+                guard let files = fileCounts[type] else { continue }
+
+                print("\(type) used in the following files:")
+                files
+                    .map({  " \($0.pathString)" })
+                    .forEach { print($0) }
+            }
+        }
+
         return typeUsages
     }