Add method to remove all handlers (#36)

Co-authored-by: Sindre Sorhus <sindresorhus@gmail.com>

Sources/KeyboardShortcuts/KeyboardShortcuts.swift

@@ -46,6 +46,18 @@ public enum KeyboardShortcuts {
 		// TODO: Should remove user defaults too.
 	}
 
+	/**
+	Remove all handlers receiving keyboard shortcuts events.
+	
+	This can be used to reset the handlers before re-creating them to avoid having multiple handlers for the same shortcut.
+	*/
+	public static func removeAllHandlers() {
+		keyDownHandlers = [:]
+		keyUpHandlers = [:]
+		userDefaultsKeyDownHandlers = [:]
+		userDefaultsKeyUpHandlers = [:]
+	}
+
 	// TODO: Also add `.isEnabled(_ name: Name)`.
 	/**
 	Disable a keyboard shortcut.