Fix logger truncate for multi-byte characters (#9767)

Author: akash-akya

lib/logger/lib/logger/utils.ex

@@ -81,7 +81,7 @@ defmodule Logger.Utils do
   end
 
   defp fix_binary(<<h, t::binary>>, acc) do
-    fix_binary(t, <<h, acc::binary>>)
+    fix_binary(t, <<acc::binary, h>>)
   end
 
   defp fix_binary(<<>>, _acc) do

lib/logger/test/logger/utils_test.exs

@@ -23,6 +23,7 @@ defmodule Logger.UtilsTest do
     assert truncate("olá", 4) == "olá"
     assert truncate("ááááá:", 10) == ["ááááá", " (truncated)"]
     assert truncate("áááááá:", 10) == ["ááááá", " (truncated)"]
+    assert truncate("𠜎𠜱𠝹𠱓", 15) == ["𠜎𠜱𠝹", " (truncated)"]
 
     # Charlists
     assert truncate('olá', 2) == ['olá', " (truncated)"]