Automatic Unicode decoding for python3 plugins

- In Vim :py3 returns unicode strings to the caller, for compatibility
  automatic decoding is now enabled for plugins in python3

Author: equalsraf

neovim/plugins/script_host.py

@@ -2,7 +2,7 @@
 import logging
 import sys
 
-from ..api.common import SessionHook
+from ..api.common import SessionHook, DecodeHook
 from ..compat import NUM_TYPES, IS_PYTHON3
 
 
@@ -26,6 +26,8 @@ def __init__(self, nvim):
         # it seems some plugins assume 'sys' is already imported, so do it now
         exec('import sys', self.module.__dict__)
         sys.modules['vim'] = nvim.with_hook(LegacyEvalHook())
+        if IS_PYTHON3:
+            sys.modules['vim'] = sys.modules['vim'].with_hook(DecodeHook(encoding=nvim.options['encoding'].decode('ascii')))
 
     def python_execute(self, script):
         exec(script, self.module.__dict__)