Feature request: Generate code coverage summary information similar to solidity-coverage

At the moment `hevm dapp-test --coverage` outputs the source code files with some symbols in front of each line, which indicates if those lines were covered or not, or if they can't be covered. However, it does not give an indication of what percentage of instructions were covered or what the branch coverage is.

The percentages mentioned above, which some people find quite useful, are given by solidity-coverage in the form of a table (see attached image)

If there are more people out there who would like to get that information from this tool, let's make it known to the team. Hopefully they will implement it when/if they find the time for it.