[mod] remove unused import

use
from searx.engines.duckduckgo import _fetch_supported_languages, supported_languages_url  # NOQA
so it is possible to easily remove all unused import using autoflake:
autoflake --in-place --recursive --remove-all-unused-imports searx tests

searx/engines/deviantart.py

@@ -15,7 +15,6 @@
 from lxml import html
 import re
 from urllib.parse import urlencode
-from searx.utils import extract_text
 
 
 # engine dependent config