[11.x] Fixes doc block in Connector.php

[saMahmoudzadeh]

This PR, fixes doc block in tryAgainIfCausedByLostConnection method.

The @throws \Exception has been changed to @throws \Throwable, which seems more appropriate, as the parameter $e is of type Throwable.

Additionally, Exception itself extends Throwable.

// Before
* @throws \Exception
*/
protected function tryAgainIfCausedByLostConnection(Throwable $e, $dsn, $username, $password, $options)

// After
* @throws \Throwable
*/
protected function tryAgainIfCausedByLostConnection(Throwable $e, $dsn, $username, $password, $options)

[driesvints]

Thanks!