[fix] utils: truncated result (#4949)
Make sure to prase everything before returning.
Related: \
```
FAIL: test_html_to_text (tests.unit.test_utils.TestUtils.test_html_to_text)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/home/runner/work/searxng/searxng/tests/unit/test_utils.py", line 53, in test_html_to_text
self.assertEqual(utils.html_to_text(r"regexp: (?<![a-zA-Z]"), "regexp: (?<![a-zA-Z]")
~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 'regexp: (?' != 'regexp: (?<![a-zA-Z]'
- regexp: (?
+ regexp: (?<![a-zA-Z]
```