Suggestions on multi-line comments should use the same lines

Problem to solve

As a developer, when I create a multi-line comment, I comment on the last line I want and use the dropdown to expand to the first line I want. This is a great new feature and I love it! However, if I then try to add a suggestion, it inserts:

```suggestion:-0+0
baz
```

Intended users

Developers, Code Reviewers

User experience goal

This would solve the problem of needing to manually change -0 to -2 to match the change I already made via drop-down as well as copy-pasting foo and bar from the diff (for example, if they're long lines that I wish to only change a few characters in). This reduces the effort required to make a suggestion as well as redundant specification of the lines in question.

Proposal

When adding a suggestion in an n line comment, I would like it to instead insert:

```suggestion:-n+0
foo
...
baz
```

What does success look like, and how can we measure that?

1. Create a multi-line comment on a diff.
2. Add a suggestion to the comment
3. The inserted suggestion defaults to the same number of lines as the comment and contains the same text.