If there is an explicit range associated with the comment honor this
range exactly instead of expanding the context lines above and below
where the comment is placed.
The assumption with the range is the author of the comment has
selected all of the relevant text and wants the reader of the comment
to focus on the selected region.
The automatic context lines above/below was originally added as a
workaround until multi-line range based selections were available.
With ranges commenters should not need to rely on context lines and
it may be possible to deprecate them in the future.
Change-Id: I1653a90ffa5fa99b0885a560841cfb3de3b9b11f
3fdd77ed7d