Disable play functions in docs mode, unless you set parameters.docs.autoplay

[tmeasday]

Issue: Play functions cause havoc on docs pages ;)

What I did

• Don't play unless runPlayFunction is set
• Pass that true by default
• Pass that false from the <Story> doc block, unless parameters.docs.autoplay is set

How to test

See autoplay stories, or e2e/unit tests

[shilman]

Nice one!!! 🚀

[JReinhold]

In general I think this is good, but I don't understand why autoplay and runPlayFunction are different. As far as I understand they do the exact same thing, they're just applied in different places, so I would think it was simpler if they were both called autoplay.

[tmeasday]

I guess that's a fair point. I guess my thought process was that a pithy name makes more sense for a user facing parameter (autoplay) but a longer, more descriptive name made more sense for an internal API.

However, I agree, the confusion of having different names for the same thing is not worth the dubious benefit of the above.

[tmeasday]

So the E2E test is failing for svelte SBs for a reason I think unrelated to this PR: the "primary" story in docs page isn't rendering properly:

Note, oddly, that the rest of the stories do render fine in docspage.

[shilman]

I agree with @JReinhold 's comment on renaming runPlayFunction to autoplay. Otherwise LGTM!

[tmeasday]

Changes are made, this PR is just blocked on this now.

[JReinhold]

Looks good to me. I'll investigate the Svelte issue. It's been there for a while, I guess it's just now that we're catching it in our tests.

[tmeasday]

Thanks for the assist @JReinhold !!