This updates livecheck files to use `typed: script` where feasible.
The remaining exception is `livecheck/strategy.rb`, as I wasn't
able to figure out how to resolve the typing issues around the
`@strategies` variable (I tried a couple of approaches but couldn't
find a working solution). This includes changes to resolve the other
type errors in `strategy.rb` but leaves the file as `typed: true`
for now.
When the `--extract-plist` option was added to livecheck, conditions
were added in `#run_checks` to skip casks using `ExtractPlist` if the
`--extract-plist` isn't used and the run involves multiple
formulae/casks. This integrates the skip into the `SkipConditions`
class.
The `check_for_resources` code arguably speaks for itself, so it
doesn't feel like a necessary addition. Besides that, this cleans up
some other comments and text to better align with existing examples.
