Don't allow “shift” key without other modifiers or function key

Fixes #54

Author: sindresorhus

Sources/KeyboardShortcuts/RecorderCocoa.swift

@@ -207,8 +207,9 @@ extension KeyboardShortcuts {
 					return nil
 				}
 
+				// The “shift” key is not allowed without other modifiers or a function key, since it doesn't actually work.
 				guard
-					!event.modifiers.isEmpty
+					!event.modifiers.subtracting(.shift).isEmpty
 						|| event.specialKey?.isFunctionKey == true,
 					let shortcut = Shortcut(event: event)
 				else {