Ruby

Please backport r61469 to ruby_2_5 branch.

2.5.0:

% rbenv exec irb -r irb/completion --simple-prompt
>> {foo: 1}.fetch(:fooo)
Traceback (most recent call last):
        3: from .../bin/irb:11:in `<main>'
        2: from (irb):1
        1: from (irb):1:in `fetch'
KeyError (key not found: :fooo
Did you mean?  :foo)

trunk:

>> {foo: 1}.fetch(:fooo)
Traceback (most recent call last):
        3: from .../bin/irb:11:in `<main>'
        2: from (irb):1
        1: from (irb):1:in `fetch'
KeyError (key not found: :fooo)
Did you mean?  :foo