[clang] [analyzer] Fix invalid HTML nesting for popups at end of line (PR #207793)

[Balázs Benics via cfe-commits]

https://github.com/steakhal approved this pull request.

Looks well motivated, well scoped and tested. Thanks for the patch.
I'd say, not something common for new contributions.
Thank you for coming. I had some inline questions but this is IMO already good to go!

https://github.com/llvm/llvm-project/pull/207793