Remove no longer needed uses of @available.

Mac/AppAssets.swift

@@ -52,7 +52,6 @@ struct AppAssets {
 		return RSImage(named: "accountTheOldReader")
 	}()
 
-	@available(macOS 11.0, *)
 	static var addNewSidebarItemImage: RSImage = {
 		return NSImage(systemSymbolName: "plus", accessibilityDescription: nil)!
 	}()
@@ -69,12 +68,10 @@ struct AppAssets {
 		return RSImage(named: "articleExtractorOn")!
 	}()
 
-	@available(macOS 11.0, *)
 	static var articleTheme: RSImage = {
 		return NSImage(systemSymbolName: "doc.richtext", accessibilityDescription: nil)!
 	}()
 
-	@available(macOS 11.0, *)
 	static var cleanUpImage: RSImage = {
 		return NSImage(systemSymbolName: "wind", accessibilityDescription: nil)!
 	}()
@@ -150,12 +147,10 @@ struct AppAssets {
 		return RSImage(named: "markAllAsRead")!
 	}()
 
-	@available(macOS 11.0, *)
 	static var nextUnreadImage: RSImage = {
 		return NSImage(systemSymbolName: "chevron.down.circle", accessibilityDescription: nil)!
 	}()
 
-	@available(macOS 11.0, *)
 	static var openInBrowserImage: RSImage = {
 		return NSImage(systemSymbolName: "safari", accessibilityDescription: nil)!
 	}()

iOS/Article/ImageScrollView.swift

@@ -344,7 +344,6 @@ extension ImageScrollView: UIScrollViewDelegate {
 		return false
 	}
 	
-	@available(iOS 11.0, *)
 	public func scrollViewDidChangeAdjustedContentInset(_ scrollView: UIScrollView) {
 		imageScrollViewDelegate?.scrollViewDidChangeAdjustedContentInset?(scrollView)
 	}
@@ -357,5 +356,4 @@ extension ImageScrollView: UIScrollViewDelegate {
 		adjustFrameToCenter()
 		imageScrollViewDelegate?.scrollViewDidZoom?(scrollView)
 	}
-	
 }