Reflection: Nitpicks, NFC

Author: slavapestov

include/swift/Reflection/ReflectionContext.h

@@ -261,9 +261,11 @@ class ReflectionContext {
 
 public:
 
-  ReflectionContext(std::shared_ptr<MemoryReader> Reader)
+  explicit ReflectionContext(std::shared_ptr<MemoryReader> Reader)
     : Reader(Reader) {}
 
+  ReflectionContext(const ReflectionContext&) = delete;
+
   MemoryReader &getReader() {
     return *Reader;
   }