<ins> in NOTE section needs more contrast

[arai-a]

https://arai-a.github.io/ecma262-compare/?pr=3000&id=sec-rules-of-automatic-semicolon-insertion

There's inserted block inside NOTE block, where both uses green background and the color is almost same.
it needs to be tweaked:

• add border to ins
• change color of either NOTE or ins
• something else?

[arai-a]

prototype 1: use darker background for ins, if it's inside note

prototype 2: use gradient for the note, to make the most of the content's background same as normal block

unfortunately, due to ins being inline element, ins cannot have the border when the content is block element, and we cannot have consistent border, unless we change the markup somehow