Merge branch 'master' into jgrpp-beta

# Conflicts:
#	.github/workflows/commit-checker.yml
#	src/company_cmd.cpp
#	src/console_cmds.cpp
#	src/crashlog.cpp
#	src/lang/english.txt
#	src/lang/german.txt
#	src/lang/indonesian.txt
#	src/lang/japanese.txt
#	src/lang/korean.txt
#	src/lang/swedish.txt
#	src/linkgraph/linkgraphjob.cpp
#	src/linkgraph/mcf.cpp
#	src/network/core/tcp.cpp
#	src/network/core/tcp.h
#	src/network/core/tcp_game.h
#	src/network/core/udp.h
#	src/network/network.cpp
#	src/network/network_admin.cpp
#	src/network/network_admin.h
#	src/network/network_chat_gui.cpp
#	src/network/network_client.cpp
#	src/network/network_client.h
#	src/network/network_func.h
#	src/network/network_internal.h
#	src/network/network_server.cpp
#	src/network/network_server.h
#	src/newgrf.cpp
#	src/newgrf_station.cpp
#	src/order_gui.cpp
#	src/rail_cmd.cpp
#	src/saveload/saveload.cpp
#	src/settings.cpp
#	src/settings_gui.cpp
#	src/settings_internal.h
#	src/settings_type.h
#	src/station_cmd.cpp
#	src/stdafx.h
#	src/table/currency_settings.ini
#	src/table/misc_settings.ini
#	src/table/settings.h.preamble
#	src/table/settings.ini
#	src/terraform_cmd.cpp
#	src/timetable_gui.cpp
#	src/train_cmd.cpp
#	src/tree_cmd.cpp
#	src/water_cmd.cpp

src/core/kdtree.hpp

@@ -274,7 +274,7 @@ class Kdtree {
 	}
 
 	template <typename Outputter>
-	void FindContainedRecursive(CoordT p1[2], CoordT p2[2], size_t node_idx, int level, Outputter outputter) const
+	void FindContainedRecursive(CoordT p1[2], CoordT p2[2], size_t node_idx, int level, const Outputter &outputter) const
 	{
 		/* Dimension index of current level */
 		int dim = level % 2;
@@ -458,7 +458,7 @@ public:
 	* @param outputter Callback used to return values from the search.
 	*/
 	template <typename Outputter>
-	void FindContained(CoordT x1, CoordT y1, CoordT x2, CoordT y2, Outputter outputter) const
+	void FindContained(CoordT x1, CoordT y1, CoordT x2, CoordT y2, const Outputter &outputter) const
 	{
 		assert(x1 < x2);
 		assert(y1 < y2);