(preact-iso): Router: Fix change location after useLocation().route()

[piotr-cz]

At this moment routers' reducer dispatcher behaves as follows:

• User action (MouseEvent):
  window location is updated via history.pushState

• User navigation via back/ forward (PopStateEvent):
  window location is left intact, as it's change is handled by browser

• Manual route change via useLocation().route(path)
  window location is left intact

This PR

• Fixes last case so history.pushState is used to add new entry to browsers history and in effect location changes.
• Moves push from dispatcher argument to function code block, As reducer dispatchers consume only two arguments. it gave false indication that the argument may be chosen somehow.
• Makes it clear that in reality there is no way to set push to false and in effect use history.replaceState

[changeset-bot]

🦋 Changeset detected

Latest commit: 0bbb8cc

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
preact-iso	Patch

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[JoviDeCroock]

How can we get to the else if (push === false) history.replaceState(null, '', url); now?

[piotr-cz]

We cannot. however we never could (the UPDATE method is not exported, just the route(url) is). Now it's just obvious to notice.
Please read this PR description for explanation and try to get to evaluate history.replaceState on master branch if you can.

[developit]

Right, #413 will provide a way to use push.