minor #34519 improve upgrade instructions for twig.exception_controller configuration (bendavies)
minor #34519 improve upgrade instructions for twig.exception_controller configuration (bendavies)

This PR was merged into the 4.4 branch.

Discussion
----------

improve upgrade instructions for twig.exception_controller configuration

| Q             | A
| ------------- | ---
| Branch?       | 4.4
| Bug fix?      | no
| New feature?  | no
| Deprecations? | no
| Tickets       |
| License       | MIT
| Doc PR        |

This improves the upgrade instructions for the deprecated configuration of `twig.exception_controller`.

Or would it be better to make the default `null` on 4.4?
https://github.com/symfony/symfony/blob/a8a9e69488fdaf609fecacba66e056ffb8f25da8/src/Symfony/Bundle/TwigBundle/DependencyInjection/Configuration.php#L41

Commits
-------

bdc68fd894 improve upgrade instructions for twig.exception_controller configuration

tucksaun/symfony,stof/symfony,mweimerskirch/symfony,1ed/symfony,ogizanagi/symfony,damienalexandre/symfony,d-ph/symfony,mweimerskirch/symfony,pyrech/symfony,derrabus/symfony,kbond/symfony,hhamon/symfony,Slamdunk/symfony,hhamon/symfony,chalasr/symfony,maidmaid/symfony,gonzalovilaseca/symfony,localheinz/symfony,OskarStark/symfony,gonzalovilaseca/symfony,damienalexandre/symfony,pierredup/symfony,bendavies/symfony,jvasseur/symfony,derrabus/symfony,Slamdunk/symfony,HeahDude/symfony,pyrech/symfony,mpdude/symfony,sgehrig/symfony,smatyas/symfony,paradajozsef/symfony,jderusse/symfony,lyrixx/symfony,ro0NL/symfony,d-ph/symfony,fabpot/symfony,symfony/symfony,smatyas/symfony,phramz/symfony,Koc/symfony,d-ph/symfony,d-ph/symfony,oleg-andreyev/symfony,dmaicher/symfony,hhamon/symfony,mnapoli/symfony,tucksaun/symfony,phramz/symfony,zerkms/symfony,lstrojny/symfony,maidmaid/symfony,fabpot/symfony,Taluu/symfony,phramz/symfony,chalasr/symfony,paradajozsef/symfony,zerkms/symfony,Simperfit/symfony,curry684/symfony,jakzal/symfony,bendavies/symfony,Simperfit/symfony,gonzalovilaseca/symfony,symfony/symfony,alekitto/symfony,Tobion/symfony,pierredup/symfony,voronkovich/symfony,OskarStark/symfony,Taluu/symfony,Taluu/symfony,Simperfit/symfony,kbond/symfony,zerkms/symfony,symfony/symfony,pyrech/symfony,jderusse/symfony,1ed/symfony,mnapoli/symfony,Tobion/symfony,sgehrig/symfony,tgalopin/symfony,voronkovich/symfony,oleg-andreyev/symfony,jderusse/symfony,Deamon/symfony,zorn-v/symfony,Deamon/symfony,smatyas/symfony,garak/symfony,ogizanagi/symfony,jakzal/symfony,bendavies/symfony,zerkms/symfony,Koc/symfony,voronkovich/symfony,oleg-andreyev/symfony,Nyholm/symfony,damienalexandre/symfony,HeahDude/symfony,paradajozsef/symfony,Deamon/symfony,xabbuh/symfony,smatyas/symfony,Taluu/symfony,mnapoli/symfony,ro0NL/symfony,ragboyjr/symfony,Nyholm/symfony,garak/symfony,nicolas-grekas/symfony,curry684/symfony,dmaicher/symfony,ragboyjr/symfony,mpdude/symfony,mnapoli/symfony,zorn-v/symfony,jvasseur/symfony,Slamdunk/symfony,phramz/symfony,xabbuh/symfony,kbond/symfony,lstrojny/symfony,1ed/symfony,derrabus/symfony,derrabus/symfony,MatTheCat/symfony,jderusse/symfony,ro0NL/symfony,jakzal/symfony,nicolas-grekas/symfony,tgalopin/symfony,MatTheCat/symfony,Simperfit/symfony,nicolas-grekas/symfony,dmaicher/symfony,1ed/symfony,lyrixx/symfony,alekitto/symfony,tgalopin/symfony,dmaicher/symfony,mnapoli/symfony,OskarStark/symfony,shieldo/symfony,jvasseur/symfony,ro0NL/symfony,MatTheCat/symfony,lstrojny/symfony,maidmaid/symfony,chalasr/symfony,stof/symfony,tgalopin/symfony,tucksaun/symfony,fabpot/symfony,HeahDude/symfony,symfony/symfony,stof/symfony,Koc/symfony,chalasr/symfony,ogizanagi/symfony,Deamon/symfony,gonzalovilaseca/symfony,smatyas/symfony,alekitto/symfony,shieldo/symfony,hhamon/symfony,paradajozsef/symfony,MatTheCat/symfony,maidmaid/symfony,jvasseur/symfony,HeahDude/symfony,lyrixx/symfony,alekitto/symfony,sgehrig/symfony,sgehrig/symfony,Koc/symfony,mweimerskirch/symfony,pierredup/symfony,garak/symfony,Tobion/symfony,ragboyjr/symfony,Slamdunk/symfony,Nyholm/symfony,tucksaun/symfony,Tobion/symfony,kbond/symfony,xabbuh/symfony,pierredup/symfony,shieldo/symfony,ragboyjr/symfony,curry684/symfony,nicolas-grekas/symfony,garak/symfony,stof/symfony,localheinz/symfony,mpdude/symfony,voronkovich/symfony,jakzal/symfony,bendavies/symfony,zorn-v/symfony,curry684/symfony,Simperfit/symfony,ogizanagi/symfony,pyrech/symfony,Nyholm/symfony,xabbuh/symfony,localheinz/symfony,OskarStark/symfony,mpdude/symfony,oleg-andreyev/symfony,damienalexandre/symfony,mweimerskirch/symfony,mweimerskirch/symfony,localheinz/symfony,zorn-v/symfony,Deamon/symfony,fabpot/symfony,shieldo/symfony,lyrixx/symfony