📝 Fix NatSpec and comment typos across ERC4626 and FixedPointMathLib

[BhariGowda]

Small documentation fixes found while auditing the codebase.

ERC4626.sol — line 330

• "minter" → "minted"

FixedPointMathLib.sol — lines 1181, 1199

• "begins == end" → "begin == end" (both lerp overloads)

FixedPointMathLib.sol — lines 492-493

• "is correct / correct for" → "is correct / for" (duplicate word)