Feature Request: skip_last_lines (in addition to skip_lines=x)

When running keep-sorted in our ruby code base, we have the following syntax that wraps arrays

```ruby
# keep-sorted start
SOME_ARRAY = %w[
AAA
BBB
CCC
].freeze
# keep-sorted end
```

**We are unable to nest the `# keep-sorted start/end` within the array because of the `%w`. E.g. this is incorrect**
```ruby
SOME_ARRAY = %w[
# keep-sorted start
AAA
BBB
CCC
# keep-sorted end
].freeze
```

What we're doing as somewhat of a workaround, which we believe is effectively sorting the last row `].freeze` as well (which would be incorrect)

```ruby
# keep-sorted start skip_lines=1 block=yes
SOME_ARRAY = %w[
AAA
BBB
CCC
].freeze
# keep-sorted end

```

The feature request is to add a syntax that allows something like this:

```ruby
# keep-sorted start skip_lines=1 skip_last_lines=1 block=yes
SOME_ARRAY = %w[
AAA
BBB
CCC
].freeze
# keep-sorted end
```