[v4] Hook docs

[ChefMist]

Add a section to remind devs about bin pool. eg.

1/ assume active bin ratio is 40% usdc/ 60% usdt
2/ user add liquidity for the active bin with just usdt. it will get swapped to 40% usdc / 60% usdt
3/ user burn and will get 40% usdc / 60% usdt.

User might perform the above to evade beforeSwap() fee. hooks might want to guard against that in mint call with HOOKS_AFTER_MINT_OFFSET