Do not delete comments when removing unused declarations

[dialex]

• VSCode Version: 1.39.2
• OS Version: macOS 10.14.6

Steps to Reproduce:

1. Write a comment
2. Declare some JS variables and use them
3. Declare some unused JS variables
4. Click the tooltip and select "Delete al unused declarations

Expected:

• Comments are not deleted
• Unused declarations are removed

Actual

• Comments are deleted

Does this issue occur when all extensions are disabled?: Yes

[mjbvz]

This was previously reported in #24758

Moving upstream for more feedback

[jessetrinity]

@mjbvz Which comments are desirable to remove? There seems to be some opinion that only doc comments should be left in place, but the comment on #24758 indicates that all comments are desirable:

// section comment
const ununsed = 0;
// other comment
const used = 0;

becomes

// section comment
// other comment
const used = 0;

I assume variable declarations are not a special case and we want to do the same for methods?

// comment
function unused(){}
// comment
function used(){}

becomes

// comment
// comment
function used(){}

Imports are currently special cased so that comments preceding only the first import are preserved. Do we want to change this for imports as well?

// tslint:disable:no-console
import unused from "module"
// comment
import used from "otherModule"

becomes

// tslint:disable:no-console
// comment
import used from "otherModule"

TL;DR where shouldn't we leave leading comments when we delete an unused variable?