Renaming toggle to toggleVisibility because it was conflicting with sidebar and breaking it

[aghassemi]

Sidebar registers an action named toggle therefore we can not register toggle as a global action and not break backward compatibility. Renaming to toggleVisibility

/to @alanorozco
/cc @muxin Needs to be merged before Canary Cut

[aghassemi]

@dvoytenko

[alanorozco]

Could we potentially consider an implementation that allows elements to override a global action?

[aghassemi]

@alanorozco that's a good idea. let me see if I can implement that approach instead.

[aghassemi]

@alanorozco @dvoytenko Alright I tried to provide a way for elements to override global actions that work in 99.9% of the cases but has a race condition that is not acceptable IMO. Details and implementation in this PR: #7912

Having a feature to allow overriding global actions by elements aside, I still like to proceed with this PR for a different reason:

Although toggle is a nice symmetric name to complement hide and show, it is still too generic and its meaning is derived based on the element it is acting on. For instance, it makes a lot of sense to add a toggle function to accordion to toggle between expanded/collapsed states, but that nothing to do with toggling visibility. So toggleVisibility as the global action is more clear and explicit.

[alanorozco]

@aghassemi Makes sense.

[dvoytenko]

@aghassemi @alanorozco I think in reality, the risk condition would be triggered much more often. It'd be nice, I agree. But since we can't know whether or not the element overrides an action until it was fully downloaded, this might be too prohibitive.