Add bugprone-use-after-move

It's generally bad practice to use something after it's been std::moved
from.

.clang-tidy

@@ -1,4 +1,4 @@
 ---
-Checks:          '-*,modernize-use-nullptr,performance-unnecessary-value-param'
+Checks:          '-*,bugprone-use-after-move,modernize-use-nullptr,performance-unnecessary-value-param'
 WarningsAsErrors: true
 ...

src/gui/dialogs/story_viewer.cpp

@@ -370,7 +370,6 @@ void story_viewer::draw_floating_image(floating_image_list::const_iterator image
 		image["name"] = floating_image.file();
 		config cfg{"image", std::move(image)};
 
-		cfg.add_child("image", std::move(image));
 		window_canvas.append_cfg(std::move(cfg));
 
 		// Needed to make the background redraw correctly.

src/gui/widgets/pane.cpp

@@ -130,12 +130,13 @@ unsigned pane::create_item(const widget_data& item_data,
 		}
 	}
 
+    const auto item_id = item.id;
 	items_.push_back(std::move(item));
 
 	event::message message;
 	fire(event::REQUEST_PLACEMENT, *this, message);
 
-	return item.id;
+	return item_id;
 }
 
 void pane::place(const point& origin, const point& size)

src/help/help_impl.cpp

@@ -918,7 +918,7 @@ void generate_races_sections(const config* help_cfg, section& sec, int level)
 	bool process_queue_again = true;
 	while(process_queue_again && !taxonomy_queue.empty()) {
 		process_queue_again = false;
-		std::vector<taxonomy_queue_type> to_process = std::move(taxonomy_queue);
+		auto to_process = std::exchange(taxonomy_queue, {});
 
 		for(auto& x : to_process) {
 			auto parent = find_section(sec, x.parent_id);