Add explanations for invariant ratios to the amm build page

[mkflow27]

Additional explanations in the docs page about invariant ratios are needed

    /// @inheritdoc IUnbalancedLiquidityInvariantRatioBounds
    function getMinimumInvariantRatio() external pure returns (uint256) {
        return WeightedMath._MIN_INVARIANT_RATIO;
    }

    /// @inheritdoc IUnbalancedLiquidityInvariantRatioBounds
    function getMaximumInvariantRatio() external pure returns (uint256) {
        return WeightedMath._MAX_INVARIANT_RATIO;
    }