add missing header end comments

- ensures a consistent usage in header files
- also add a blank line after the copyright header where missing
- also remove orphan new-lines at the end of some files

src/init.h

@@ -33,4 +33,4 @@ std::string HelpMessage(HelpMessageMode mode);
 /** Returns licensing information (for -version) */
 std::string LicenseInfo();
 
-#endif
+#endif // BITCOIN_INIT_H