Scrub only after converting strings to UTF-8
Scrub only after converting strings to UTF-8

Scrubbing an ASCII-8BIT string isn't ever going to remove anything, because
there's no code point that isn't valid 8-bit ASCII.  Since we'd really
prefer it if everything were UTF-8 anyway, we'll just assume, for now, that
whatever comes out of SimpleRSS is probably UTF-8, and just nuke anything
that isn't a valid UTF-8 codepoint.

Of course, the *real* bug here is that SimpleRSS [unilaterally converts
everything to
ASCII-8BIT](https://github.com/cardmagic/simple-rss/issues/15).  It's
presumably *far* too much to ask that it detects the encoding of the source
RSS feed and marks the parsed strings with the correct encoding...

natefinch/discourse,natefinch/discourse