Fix an edgecase bug for no_trailing_semicolons

This is to fix an edge case bug where, inside of a multiline string,
there is an interpolated string where the entire interpolation is a
function call and does not contain a variable/string.

Fixes #314
Merge pull request #315 from swang/fix_edgecase_for_no_trailing_semicolons

Fix an edgecase bug for no_trailing_semicolons