Store errors from TLS write and handshake in the tls_error field.

Previously, we would only update this field when the error happened
during a read.

This will improves our reporting for our bootstrap status, and help
to address #32622.  The problem is not completely solved by this
patch, however: too many errors are still lumped into "MISC".

src/core/mainloop/connection.c

@@ -4205,6 +4205,7 @@ connection_handle_write_impl(connection_t *conn, int force)
     switch (result) {
       CASE_TOR_TLS_ERROR_ANY:
       case TOR_TLS_CLOSE:
+        or_conn->tls_error = result;
         log_info(LD_NET, result != TOR_TLS_CLOSE ?
                  "tls error. breaking.":"TLS connection closed on flush");
         /* Don't flush; connection is dead. */