swap order of encoder search

As described by @scott-r in
Magic encoder does not use
previously used code pages
when possible #570
Thank you!

CHANGELOG.rst

@@ -12,11 +12,15 @@ changes
 - has
 - changed
 
+- fix the encoding search so that lower encodings are found first
+
 contributors
 ^^^^^^^^^^^^
 - list
 - contributors
 
+- scott-r in [#570](https://github.com/python-escpos/python-escpos/issues/570)
+
 2023-05-11 - Version 3.0a9 - "Pride Comes Before A Fall"
 --------------------------------------------------------
 This release is the 10th alpha release of the new version 3.0.

src/escpos/magicencode.py

@@ -155,7 +155,8 @@ class Encoder(object):
 
     def __encoding_sort_func(self, item):
         key, index = item
-        return (key in self.used_encodings, index)
+        used = key in self.used_encodings
+        return (not used, index)
 
     def find_suitable_encoding(self, char):
         """Search in a specific order for a suitable encoding.