docs: improve slot0 function return value documentation

[Caplost]

Description

Improve the documentation format for the slot0() function in IUniswapV3PoolState.sol. Add proper @return tags for all return values to maintain consistent documentation style.

Changes

• Add @return tags for all return parameters in slot0() function
• Maintain detailed descriptions while improving readability
• Keep consistent documentation format across the interface

Before

/// @return sqrtPriceX96 The current price of the pool as a sqrt(token1/token0) Q64.96 value
/// tick The current tick of the pool, i.e. according to the last tick transition that was run.
/// This value may not always be equal to SqrtTickMath.getTickAtSqrtRatio(sqrtPriceX96) if the price is on a tick
/// boundary.
/// observationIndex The index of the last oracle observation that was written,
/// observationCardinality The current maximum number of observations stored in the pool,
/// observationCardinalityNext The next maximum number of observations, to be updated when the observation.
/// feeProtocol The protocol fee for both tokens of the pool.
/// Encoded as two 4 bit values, where the protocol fee of token1 is shifted 4 bits and the protocol fee of token0
/// is the lower 4 bits. Used as the denominator of a fraction of the swap fee, e.g. 4 means 1/4th of the swap fee.
/// unlocked Whether the pool is currently locked to reentrancy

After

/// @return sqrtPriceX96 The current price of the pool as a sqrt(token1/token0) Q64.96 value
/// @return tick The current tick of the pool, i.e. according to the last tick transition that was run.
/// This value may not always be equal to SqrtTickMath.getTickAtSqrtRatio(sqrtPriceX96) if the price is on a tick boundary.
/// @return observationIndex The index of the last oracle observation that was written
/// @return observationCardinality The current maximum number of observations stored in the pool
/// @return observationCardinalityNext The next maximum number of observations, to be updated when the observation
/// @return feeProtocol The protocol fee for both tokens of the pool. Encoded as two 4 bit values, where the protocol fee of token1
/// is shifted 4 bits and the protocol fee of token0 is the lower 4 bits. Used as the denominator of a fraction of the swap fee,
/// e.g. 4 means 1/4th of the swap fee.
/// @return unlocked Whether the pool is currently locked to reentrancy

Type of change

Documentation update (non-breaking change)

Checklist

• Documentation update only
• No code changes
• No breaking changes
• Maintains all technical details while improving format