[NFC] Fix out-of-date documentation related to ModuleLoaders.

Author: varungandhi-apple

Diff for: include/swift/Serialization/SerializedModuleLoader.h

@@ -31,8 +31,8 @@ enum class ModuleLoadingMode {
   OnlySerialized
 };
 
-/// Common functionality shared between \c SerializedModuleLoader and
-/// \c ModuleInterfaceLoader.
+/// Common functionality shared between \c SerializedModuleLoader,
+/// \c ModuleInterfaceLoader and \c MemoryBufferSerializedModuleLoader.
 class SerializedModuleLoaderBase : public ModuleLoader {
   /// A { module, generation # } pair.
   using LoadedModulePair = std::pair<std::unique_ptr<ModuleFile>, unsigned>;

Diff for: lib/AST/ModuleLoader.cpp

@@ -39,7 +39,6 @@ DependencyTracker::addDependency(StringRef File, bool IsSystem) {
   // DependencyTracker exposes an interface that (intentionally) does not talk
   // about clang at all, nor about missing deps. It does expose an IsSystem
   // dimension, which we accept and pass along to the clang DependencyCollector.
-  // along to the clang DependencyCollector.
   clangCollector->maybeAddDependency(File, /*FromModule=*/false,
                                      IsSystem, /*IsModuleFile=*/false,
                                      /*IsMissing=*/false);