unit_recruit: Show unrecruitable units in gray, rather than red

Matches new unit_recall behavior

(cherry picked from commit cb07373)

src/gui/dialogs/unit_recruit.cpp

@@ -13,6 +13,7 @@
 
 #define GETTEXT_DOMAIN "wesnoth-lib"
 
+#include "font/text_formatting.hpp"
 #include "gui/auxiliary/find_widget.hpp"
 #include "gui/dialogs/unit_recruit.hpp"
 #include "gui/widgets/button.hpp"
@@ -52,9 +53,11 @@ unit_recruit::unit_recruit(std::vector<const unit_type*>& recruit_list, team& te
 	});
 }
 
-static std::string can_afford_unit(const std::string& text, const bool can_afford)
+static const color_t inactive_row_color(0x96, 0x96, 0x96);
+
+static inline std::string can_afford_unit(const std::string& text, const bool can_afford)
 {
-	return can_afford ? text : "<span color='#ff0000'>" + text + "</span>";
+	return can_afford ? text : font::span_color(inactive_row_color, text);
 }
 
 // Compare unit_create::filter_text_change
@@ -139,7 +142,7 @@ void unit_recruit::pre_show(window& window)
 
 		column["use_markup"] = "true";
 
-		column["label"] = image_string;
+		column["label"] = image_string + (can_afford ? "" : "~GS()");
 		row_data.emplace("unit_image", column);
 
 		column["label"] = can_afford_unit(recruit->type_name(), can_afford);
@@ -148,7 +151,12 @@ void unit_recruit::pre_show(window& window)
 		column["label"] = can_afford_unit(cost_string, can_afford);
 		row_data.emplace("unit_cost", column);
 
-		list.add_row(row_data);
+		grid& grid = list.add_row(row_data);
+		if(!can_afford) {
+			image *gold_icon = dynamic_cast<image*>(grid.find("gold_icon", false));
+			assert(gold_icon);
+			gold_icon->set_image(gold_icon->get_image() + "~GS()");
+		}
 	}
 
 	list_item_clicked(window);