Rename operations to their full name(add -> addition, mul -> multiplication)

[AlbertSu123]

Solidity gives the following warning when a instruction from a contract has the same name as an instruction in solidity's assembly.

Warning: Variable is shadowed in inline assembly by an instruction of the same name
--> prb-math/contracts/PRBMathUD60x18.sol:75:5:
75 | function div(uint256 x, uint256 y) internal pure returns (uint256 result) {
| ^ (Relevant source part starts here and spans across multiple lines).

Would you accept a pull request that renames all conflicting operations with their full instruction name?

[PaulRBerg]

Closing, duplicate of #35. Let's move the discussion there.

Can you try bump the version of the Solidity compiler to the latest version (0.8.4) and see if that makes the warnings go away?