[IMP] snippets: prepare for changed default in python 3.14

Cited from documentation:
> Note  The default multiprocessing start method (see Contexts and start
> methods) will change away from fork in Python 3.14. Code that requires fork
> be used for their ProcessPoolExecutor should explicitly specify that by
> passing a `mp_context=multiprocessing.get_context("fork")` parameter.[^1]

[^1]: https://docs.python.org/3/library/concurrent.futures.html#processpoolexecutor

Author: cawo-odoo

src/util/snippets.py

@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
 import inspect
 import logging
+import multiprocessing
 import re
 import sys
 import uuid
@@ -305,7 +306,7 @@ def convert_html_columns(cr, table, columns, converter_callback, where_column="I
     update_sql = ", ".join(f'"{column}" = %({column})s' for column in columns)
     update_query = f"UPDATE {table} SET {update_sql} WHERE id = %(id)s"
 
-    with ProcessPoolExecutor(max_workers=get_max_workers()) as executor:
+    with ProcessPoolExecutor(max_workers=get_max_workers(), mp_context=multiprocessing.get_context("fork")) as executor:
         convert = Convertor(converters, converter_callback)
         for query in log_progress(split_queries, logger=_logger, qualifier=f"{table} updates"):
             cr.execute(query)