comment generate is very bad

[janryWang]

Motivation

Describe cases that motivate the implementation of the expected behavior.

var x = (a + b /* 123*/ ) * c

Expected behavior

Describe how the feature should work.

var x = (a + b /* 123*/ ) * c

Actual behavior

var x = (a + b ) * c

Describe the actual behavior of the feature or remove this section if the feature has not been implemented yet.

[davidbonnet]

Relates to #562

[davidbonnet]

Bottom line: Astring should indeed produce comments as close as possible to the original source code.