add-exception-option

[masarakki]

it makes easy to give up and continue

Naming of exception is a semi-standard name after ruby-2.6.0
https://bugs.ruby-lang.org/issues/12732
https://bugs.ruby-lang.org/issues/14386

[nfedyashev]

Hi @masarakki !

Thanks for your pull request!
I've reviewed it and unfortunately decided not to accept it at this moment. Here's why:

• although I understand it could be useful for some users I suspect that percent of such users is quite low.
• it adds additional cognitive complexity on user while he reads documentation and current configuration option is already quite complicated.
• those users who actually need this functionality can just wrap the whole retryable block in its own begin/rescue block. I believe that it would be more explicit and transparent solution for average user then noticing :exception => false config option.
• I believe that exception: false config option is not intuitively obvious option for an average retryable user and I would like to keep the docs and configuration as simple as possible.

On the other hand I might be getting back to this pull request later as ruby-2.6 gets more wide spread and more users will become familiar with this exception: false convention/standard.