changing default value of useBootstrap

[tisdall]

jquery-confirm version: v3.3.4

I'm submitting a ... (check one with "x") [X] bug report [ ] feature request [ ] support request

Current behavior: The docs talk about setting the default setting for useBootstrap, but it's incorrect.

jconfirm.defaults.useBootstrap = false throws an error as defaults is undefined.

I believe it should be jconfirm.pluginDefaults.useBootstrap = false

[tisdall]

... it looks like there's more instances in the docs to jconfirm.defaults that should be changed to jconfirm.pluginDefaults.