Consistently use "pickleable" instead of "picklable"
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It looks like your PR relates to the Keras component. Please submit it to the github.com/keras-team/keras repository instead. Thank you.
@fchollet, @qlzh727 Hi @NicoWeio Sorry for the delay. It looks like your PR relates to the Keras component. Please submit it to the github.com/keras-team/keras repository instead. Thankyou.
@fchollet, @qlzh727
Just a nitpick: All functions use `pickleable`, but in some parts of the documentation it's called `picklable`. This is hereby fixed.
Note that I am not a native English speaker, but the [Wiktionary](https://en.wiktionary.org/wiki/pickleable) agrees.