Merge branch 'master' into jgrpp

# Conflicts:
#	src/error.h
#	src/error_gui.cpp
#	src/linkgraph/linkgraph_gui.cpp
#	src/misc_gui.cpp
#	src/newgrf_gui.cpp
#	src/news_gui.cpp
#	src/rail_cmd.cpp
#	src/saveload/gamelog_sl.cpp
#	src/script/api/script_text.cpp
#	src/script/script_instance.cpp
#	src/statusbar_gui.cpp
#	src/strings.cpp
#	src/strings_func.h
#	src/strings_internal.h
#	src/table/settings/gui_settings.ini
#	src/table/settings/linkgraph_settings.ini
#	src/textbuf_gui.h

src/music_gui.cpp

@@ -650,7 +650,7 @@ static const NWidgetPart _nested_music_track_selection_widgets[] = {
 };
 
 static WindowDesc _music_track_selection_desc(
-	WDP_AUTO, "music_track", 0, 0,
+	WDP_AUTO, nullptr, 0, 0,
 	WC_MUSIC_TRACK_SELECTION, WC_NONE,
 	0,
 	_nested_music_track_selection_widgets, lengthof(_nested_music_track_selection_widgets)