Sticky Comments

[brodieG]

Would allow using comments as a sort of subsection, for example in:

## A comment
test1
test2   ## extra

test3

## Another comment
test4
test5 

The review prompts would look like:

## A comment
test1
---
## A comment
## extra
test2
---
test3
---
## Another Comment
test4
---
## Another Comment
test5

Notice test 3 doesn't have a comment as it got cleared by the newline.