Sourcery: keep "for-append-to-extend" check disabled

This is another check that suggests changes an average developer without
profound Python experience would find hard to understand. Disable it.

See for reference:
https://docs.sourcery.ai/Reference/Python/Default-Rules/for-append-to-extend/

scripts/.sourcery.yaml

@@ -6,6 +6,8 @@ rule_settings:
   - default
 
   disable:
+  # Might make the code more pythonic, but takes more time to understand
+  - for-append-to-extend
   # Code is easier to read without this
   - min-max-identity
   # Keep explicit lower range limit instead of using implicit default value
@@ -17,7 +19,6 @@ rule_settings:
   # FIXME: verify if we want to keep the checks below.
   # If not, remove them. If yes, move them above this comment.
   - low-code-quality
-  - for-append-to-extend
 
   rule_types:
   - refactoring