Mark articles that begin with <details> as HTML (#1294)

This Brazilian news website called Tecnoblog [1] will often begin their
articles with the <details> tag, providing a short summary for them.

[1] https://tecnoblog.net/

src/librssguard/miscellaneous/textfactory.cpp

@@ -76,7 +76,7 @@ bool TextFactory::couldBeHtml(const QString& string) {
   const QString sstring = string.simplified();
 
   return sstring.startsWith(QL1S("<!")) || sstring.startsWith(QL1S("<html")) || sstring.startsWith(QL1S("<figure")) ||
-         sstring.startsWith(QL1S("<article")) || Qt::mightBeRichText(sstring);
+         sstring.startsWith(QL1S("<article")) || sstring.startsWith(QL1S("<details")) || Qt::mightBeRichText(sstring);
 }
 
 QDateTime TextFactory::parseDateTime(const QString& date_time) {