A bunch of fixes for `export` nodes

[mishoo]

js2-visit-extern-binding will now walk the bindings in proper order (left-to-right) both for import and export parents. Previously, the walker would descend into the right node first for export, with the visible bug that js2-node-at-point would not find the foo name in this case:

export { |foo as bar };

Other small fixes:

• do not extend the boundary of the foo name node in a case like this:

  export default foo     ;
  

• include the semicolon when printing nodes like the above

• fix a bunch of warnings related to length of docstrings; also type of a defcustom.

• minor cleanups

[dgutov]

Hi! Thanks for this.

Could you add a few more tests? The js2-deftest-parse macro should at least help exercise the change in the printing behavior.

[mishoo]

Could you add a few more tests? The js2-deftest-parse macro should at least help exercise the change in the printing behavior.

Yep, that's why I marked it as draft, but I didn't get to it yet... hopefully this week.