DRY advanced town help. Fix #611

src/scenedit/scen.main.cpp

@@ -67,6 +67,9 @@ std::string scenario_temp_dir_name = "ed_scenario";
 bool change_made = false, ae_loading = false;
 std::vector<fs::path> extra_scen_dirs;
 
+// Set this based on context before calling give_help():
+std::string help_text_rsrc = "";
+
 // Numbers of current areas being edited
 short cur_town;
 location cur_out;