[docs] clarified definition of "local transition" in tutorial

[mjvandermeulen]

I was confused while reading the tutorial about local transitions. The tutorial talks about removing items and words the transition in those terms, which makes the transition block a parent. BUT... then it talks about the local directive, which belongs to the block with the transition itself.

To avoid confusion I have pretty much copied the wording from the docs verbatim (https://svelte.dev/docs, search for "Local transitions only play"), since I find the wording in the docs very clear.

I have not created an issue. Please let me know if this would still be helpful or is still needed.

[bluwy]

I actually find the wording in the tutorial more concise than the docs. What if we word it slightly differently, like:

We can achieve this with a *local* transition, which only plays when the immediate parent block of the transition is added or removed:

(added "of the transition")

[mjvandermeulen]

@bluwy. Your definition is not correct: the Doc states correctly that local transitions only play when the block they belong to is added or destroyed. The definition given in the tutorial is only correct in the context of the tutorial.

For clarification: The line I removed in the PR could have read (notice emphasis)
- We can achieve this with a *local* transition, which only plays when the immediate parent block **of the item we have been focussing on** is added or removed:

To make the definition more generalized I have changed it to the wording in the PR:
Local transitions only play when the block they belong to is created or removed, not when parent blocks are created or removed.

[bluwy]

Ah alright. I think I see your point now. I still think the definition in the tutorial should be curated for that context specifically, that's probably the point of a tutorial. What if we word it something like:

- We can achieve this with a *local* transition, which only plays when the item itself is added or removed:

[mjvandermeulen]

@bluwy I would be happy to see your last wording implemented. I have one hesitation though, because of the ambiguous meaning of 'item' in this context.

To clarify, the HTML we are talking about here is:

<div transition:slide|local>
  {item} e.g.: "one"
</div>

In the reader's mind removing the 'item' could mean removing the div's innerHTML, or the whole div.

I agree with @bluwy that the wording should be curated for this context. My new suggestion is the following:

We can achieve this with a *local* transition, which only plays when the block with the transition itself is added or removed.

But, again, I'm happy with implementing @bluwy last suggestion.

[bluwy]

I like your new suggestion, and I agree that item could be ambiguous too. Feel free to make your change!

[mjvandermeulen]

@bluwy It's been 15 days since you approved my last changes. I'm not sure if the ball is in my court, or if we just have to be patiently waiting for someone with write access to merge my pull request. Please inform.

[bluwy]

I wanted to have another maintainer's opinion on this, but since it's a small change which I think makes sense, I'll go ahead and merge this. Thanks for the PR!