Fix users with @room in the name pinging the whole room when replied to

src/timeline/InputBar.cpp

@@ -375,6 +375,11 @@ InputBar::message(const QString &msg, MarkdownOverride useMarkdown, bool rainbow
     } else if (!room->reply().isEmpty()) {
         auto related = room->relatedInfo(room->reply());
 
+        // Skip reply fallbacks to users who would cause a room ping with the fallback.
+        // This should be fine, since in some cases the reply fallback can be omitted now and the
+        // alternative is worse! On Element Android this applies to any substring, but that is their
+        // bug to fix.
+        if (!related.quoted_user.startsWith("@room:")) {
             QString body;
             bool firstLine = true;
             auto lines     = related.quoted_body.splitRef(u'\n');
@@ -400,6 +405,7 @@ InputBar::message(const QString &msg, MarkdownOverride useMarkdown, bool rainbow
             else
                 text.formatted_body =
                   utils::getFormattedQuoteBody(related, msg.toHtmlEscaped()).toStdString();
+        }
 
         text.relations.relations.push_back(
           {mtx::common::RelationType::InReplyTo, related.related_event});