Force a metrics update of buffer after reload

It makes reload more robust and is in any case good enough to avoid
crash in #139091.

Fixes bug #13091.

src/Buffer.cpp

@@ -5527,6 +5527,7 @@ Buffer::ReadStatus Buffer::reload()
 	removePreviews();
 	updatePreviews();
 	errors("Parse");
+	changed(true);
 	return status;
 }