Prohibit line-based test generation for meaningless line types (comments, single brackets, etc)

[Vladislav0Art]

We are not allowing line generation for empty lines, but it can be asked for comment lines (or brackets) if it is surrounded by class/function. The result will be almost identical to the whole class test generation, but it's weird.

In the following case, we cannot generate line-based test for (*) but we can do it for (**) (likely, because this comment is considered as part of a method):

// my comment here! - not allowed for line generation (*)

// my comment here! - allowed for line generation (**)
fun multwice(a: Int) = a * 2

Solution idea: For each line generation, check if it includes something besides comments, open/closed brackets and allow generation only in such case