Bug#941007: Gedit plugin codecomment cannot be enabled (Namespace GtkSource is already loaded with version 4)

[Luca Pandolfini]

Package: gedit-plugins
Version: 3.30.1-3

When I try to enable the "code comment" Gedit plugin, I get a forbidden 
symbol in place of the checkbox. This is the error message i get from 
Gedit:

(org.gnome.gedit:24298): libpeas-WARNING **: 12:09:35.843: Error 
importing plugin 'codecomment':
Traceback (most recent call last):
   File "/usr/lib/python3.7/importlib/__init__.py", line 127, in 
import_module
     return _bootstrap._gcd_import(name[level:], package, level)
   File "<frozen importlib._bootstrap>", line 1006, in _gcd_import
   File "<frozen importlib._bootstrap>", line 983, in _find_and_load
   File "<frozen importlib._bootstrap>", line 967, in 
_find_and_load_unlocked
   File "<frozen importlib._bootstrap>", line 677, in _load_unlocked
   File "<frozen importlib._bootstrap_external>", line 728, in 
exec_module
   File "<frozen importlib._bootstrap>", line 219, in 
_call_with_frames_removed
   File "/usr/lib/x86_64-linux-gnu/gedit/plugins/codecomment.py", line 
26, in <module>
     gi.require_version('GtkSource', '3.0')
   File "/usr/lib/python3/dist-packages/gi/__init__.py", line 121, in 
require_version
     (namespace, loaded_version))
ValueError: Namespace GtkSource is already loaded with version 4
(org.gnome.gedit:24298): libpeas-WARNING **: 12:09:35.843: Error loading 
plugin 'codecomment'

Commenting out line 26 in 
/usr/lib/x86_64-linux-gnu/gedit/plugins/codecomment.py fixes the issue:

# gi.require_version('GtkSource', '3.0')

I am using Debian 5.2.9-2 (2019-08-21) x86_64 GNU/Linux kernel 
5.2.0-2-amd64
Other plugins do not seem to be affected.

Thank you very much,

Luca Pandolfini