Clarify requirement of installing solc

[CodeSandwich]

Maybe other toolkits don't require solc either, I didn't have a chance to find out.

[CLAassistant]

All committers have signed the CLA.

[montyly]

Thanks CodeSandwich for the contribution. Actually this statement is true for any compilation platform, not just foundry (including hardhat, truffle, brownie, ...).

Maybe we could say something like [solc](https://github.com/ethereum/solidity/), the Solidity compiler, or any [supported compilation framework](https://github.com/crytic/crytic-compile)) ?

[CodeSandwich]

I didn't know that, that's pretty cool! Added.