I've just got on to this section of the course and after installing with yarn hardhat I was given slightly different options (this is based on Hardhat v2.10.0, so I selected Create a Javascript project.

The installation was all fine, however I did not have a .solhint.json file so these were the steps I followed to be able to work along with Patrick (see also the docs at https://protofire.github.io/solhint/)

• install solhint yarn add solhint
• install .solhint.json file by typing yarn solhint --init
• I then had to update the .solhint.json file as the default rules which were enabled with the --init didn't seem to work, so I replaced the text as per the docs so my .solhint.json file looks like this:

{
"extends": "solhint:recommended",
    "plugins": [],
    "rules": {
      "avoid-suicide": "error",
      "avoid-sha3": "warn"
    }
}

• I had a Lock.sol contract file instead of Greeter.sol so I made the following changes:
• change the compiler version in the contract to pragma solidity ^0.5.8; as I was receiving an error
• Then added uint256 someVar; inside the contract as per Patrick's instructions in the video, without marking the visibility
• I then ran yarn solhint contracts/*.sol in the terminal and received the following output, which includes the error we were expecting:

contracts/Lock.sol
  10:5   warning  Explicitly mark visibility of state                                                                state-visibility
  14:5   warning  Explicitly mark visibility in function (Set ignoreConstructors to true if using solidity >=0.7.0)  func-visibility
  15:9   warning  Error message for require is too long                                                              reason-string
  16:13  warning  Avoid to make time-based decisions in your business logic                                          not-rely-on-time
  28:17  warning  Avoid to make time-based decisions in your business logic                                          not-rely-on-time
  31:48  warning  Avoid to make time-based decisions in your business logic                                          not-rely-on-time

✖ 6 problems (0 errors, 6 warnings)

Done in 0.39s.

Sorry for such a long post and I'm still learning all of this, so if there is a better / more efficient way to resolve this please let me know! I wasn't sure how important this would be to the rest of the course but thought I would share in case anyone else is stuck on the same section.