Keep leadingComments of CallExpression

[morlay]

TypeScript Version: 2.3.3 +

Code

export const a = /*#__PURE__*/create("a")

Expected behavior:
CallExpression.leadingComments should have comments

Actual behavior:
in https://astexplorer.net/

[weswigham]

This will likely continue to replicate in AST explorer as an artifact of how ast explorer looks for comments, even after we fix it in our emit as we do not directly expose comments on nodes. Specifically, The leading comments of a node never include single-line multiline comments, as it is expected those will be picked up as the trailing comments of the previous node. In this case, however, the "previous node" is the identifier on the LHS of the assignment, which, when you go the get the trailing comments for, see the = sign, then stop. There are piles of cases like this, where a comment actually falls "inside" a node, and so is not picked up by the simple-thing-to-do without knowing that, say, a token was omitted from the AST at that point and that you need to collect any comments which would be considered attached to it.

Very similar to #12985; I'll add VariableDeclaration to my list at #17689.

[mhegazy]

@filipesilva mentioned he has been running into this issue as well.