Add extra check for trimming plaintext reply fallback

This should avoid most edge cases with messages starting with
blockquotes when reply fallbacks are removed.

event/reply.go

@@ -23,7 +23,7 @@ func TrimReplyFallbackHTML(html string) string {
 }
 
 func TrimReplyFallbackText(text string) string {
-	if !strings.HasPrefix(text, "> ") || !strings.Contains(text, "\n") {
+	if !strings.HasPrefix(text, "> <") || !strings.Contains(text, "\n") {
 		return text
 	}