Link graph: Fix typo in method name

src/linkgraph/linkgraph_gui.cpp

@@ -109,7 +109,7 @@ void LinkGraphOverlay::MarkStationViewportLinksDirty(const Station *st)
 /**
  * Rebuild the cache using RebuildCache, and return whether a re-draw is required.
  */
-bool LinkGraphOverlay::RebuildCacheCheckCahnged()
+bool LinkGraphOverlay::RebuildCacheCheckChanged()
 {
 	static LinkList prev_cached_links;
 	static StationSupplyList prev_cached_stations;

src/linkgraph/linkgraph_gui.h

@@ -79,7 +79,7 @@ public:
 			window(w), widget_id(wid), cargo_mask(cargo_mask), company_mask(company_mask), scale(scale), dirty(true)
 	{}
 
-	bool RebuildCacheCheckCahnged();
+	bool RebuildCacheCheckChanged();
 	void RebuildCache(bool incremental = false);
 	bool CacheStillValid() const;
 	void MarkStationViewportLinksDirty(const Station *st);

src/main_gui.cpp

@@ -271,7 +271,7 @@ struct MainWindow : Window
 			return;
 		}
 
-		if (this->viewport->overlay->RebuildCacheCheckCahnged()) {
+		if (this->viewport->overlay->RebuildCacheCheckChanged()) {
 			this->GetWidget<NWidgetBase>(WID_M_VIEWPORT)->SetDirty(this);
 		}
 	}