C#: Add some logging related to project file content.

Author: michaelnebel

csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/FileContent.cs

@@ -240,6 +240,14 @@ private void DoInitialize()
                     logger.LogDebug($"Failed to read file {file}, exception: {ex}");
                 }
             }
+
+            logger.LogInfo("Finished reading project files.");
+            logger.LogInfo($"Legacy project structure usage detected: {isLegacyProjectStructureUsed}");
+            logger.LogInfo($"New project structure usage detected: {isNewProjectStructureUsed}");
+            logger.LogInfo($"ASP.NET usage detected: {useAspNetCoreDlls}");
+            logger.LogInfo($"Windows Forms usage detected: {useWindowsForms}");
+            logger.LogInfo($"WPF usage detected: {useWpf}");
+            logger.LogInfo($"Implicit usings enabled: {useImplicitUsings}");
         }
 
         [GeneratedRegex("(?<!<!--.*)<PackageReference.*\\sInclude=\"(.*?)\".*/?>", RegexOptions.IgnoreCase | RegexOptions.Compiled | RegexOptions.Singleline)]

csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/NugetPackageRestorer.cs

@@ -149,7 +149,7 @@ public HashSet<AssemblyLookupLocation> Restore()
                     .ToList();
 
 
-                logger.LogInfo($"Restored {nugetPackageDllPaths.Count} NuGet DLLs.");
+                logger.LogInfo($"Restored {nugetPackageDllPaths.Count} NuGet DLLs from packages.config files using the NuGet CLI.");
 
                 if (excludedPaths.Count > 0)
                 {
@@ -163,7 +163,7 @@ public HashSet<AssemblyLookupLocation> Restore()
 
                 nugetPackageDllPaths.ExceptWith(excludedPaths);
 
-                logger.LogInfo($"Using {nugetPackageDllPaths.Count} NuGet DLLs as dependency candidates.");
+                logger.LogInfo($"Using {nugetPackageDllPaths.Count} DLLs as dependency candidates from NuGet packages restored via the NuGet CLI based on packages.config files.");
                 foreach (var path in nugetPackageDllPaths)
                 {
                     logger.LogDebug($"Using NuGet DLL as dependency candidate: {path}");