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/rail_gui.cpp

@@ -2338,7 +2338,7 @@ static const NWidgetPart _nested_signal_builder_widgets[] = {
 
 /** Signal selection window description */
 static WindowDesc _signal_builder_desc(
-	WDP_AUTO, "build_signal", 0, 0,
+	WDP_AUTO, nullptr, 0, 0,
 	WC_BUILD_SIGNAL, WC_BUILD_TOOLBAR,
 	WDF_CONSTRUCTION,
 	_nested_signal_builder_widgets, lengthof(_nested_signal_builder_widgets),