Fixes the semantic scholar engine by extracting a ui version token.
BTW: remove html tags from the content.
Author's checklist:
- they are ratelimiting very fast, if you do approx more than 2 requests per
minute, you have to wait some time again...
- they also have an official api at api.semanticscholar.org, but it's ratelimits
are even harder
Closes: https://github.com/searxng/searxng/issues/4685
590b211652