[Ability] Implement Unburden

[muscode13]

What are the changes the user will see?

Unburden implemented

Why am I making these changes?

Ability is not implemented

What are the changes from a developer perspective?

UnburdenBerryAbAttr - Triggers the speed boost once the user eats berries. It's based off how many they eat, so if the pokemon eats one berry they get +2, if they eat two they get +4 and so on.
UnburdenDefStolenAbAttr - This triggers if the user's item is stolen or lost when they are defending, in cases of Magician or moves like Thief, Knock Off and Pluck.
UnburdenAtkStolenAbAttr - This triggers when an item is lost during attacking, in cases like Pickpocket
pokemon.turnData.itemsLost - This variable tracks how many items the pokemon has lost during a turn. It is an integer that is used in UnburdenDefStolenAbAttr and UnburdenAtkStolenAbAttr. The integer gets decremented when an Unburden boost occurs. The integer gets incremented in various spots where items get stolen (Grip Claw, Moves, Abilities)

How to test the changes?

• Use Pokemon with Unburden in the game and give them berries. Also have a pokemon with Magician steal items from them in double battles
• run npm run test unburden

Checklist

• I'm using beta as my base branch
• There is no overlap with another PR? - I believe the other Unburden PR was closed
• The PR is self-contained and cannot be split into smaller PRs?
• Have I provided a clear explanation of the changes?
• Have I considered writing automated tests for the issue?
• If I have text, did I make it translatable and add a key in the English locale file(s)?
• Have I tested the changes (manually)?
  • Are all unit tests still passing? (npm run test)
• Are the changes visual?
  • Have I provided screenshots/videos of the changes?

[Xavion3]

This should give a battler tag that doubles speed, not directly interact with combat stages.

[muscode13]

Will do!

[muscode13]

Alright I switched it to tags! I wasn't sure if it should keep doubling speed for each item lost, but I can implement that if you guys want.

[Tempo-anon]

I think for simplicity's sake of implementation a battler tag is a fine way of going about implementation. Any item lost/used up will grant the full doubled speed boost.

Right now I believe it's missing some documentation and edge case interactions though.

[muscode13]

Alright I added documentation to the attributes, renamed them, added a test for neutralizing abilities, and accounted for getEffectiveStat

[Xavion3]

Don't double the speed twice, current it doubles in both getEffectiveStat and onAdd

[muscode13]

Don't double the speed twice, current it doubles in both getEffectiveStat and onAdd

Oh right forgot about that. Got a fix, just trying to get the Grip Claw to actually steal in my tests now

[muscode13]

OK should only be doubling in one place now

[muscode13]

Any updates? Been waiting for a review for almost a week now

[Tempo-anon]

I think functionally for the most part it is fine. The only real blocker I see is to have the neutralizing gas interaction.

Should we also slap a (P) on unburden for the weird edge cases of gaining/losing this ability though?