[win-linux] fix copyright line on About page

Author: SimplestStudio

win-linux/src/prop/cmainwindowimpl.cpp

@@ -66,7 +66,7 @@ void CMainWindowImpl::refreshAboutVersion()
 #else
     _json_obj["appname"]    = WINDOW_NAME;
 #endif
-    _json_obj["rights"]     = "© " ABOUT_COPYRIGHT_STR;
+    _json_obj["rights"]     = ABOUT_COPYRIGHT_STR;
     _json_obj["link"]       = URL_SITE;
 //    _json_obj["changelog"]  = "https://github.com/ONLYOFFICE/DesktopEditors/blob/master/CHANGELOG.md";