Some of the implicit decls generated for lazy vars have invalid source ranges.
For now, just always walk into implicit decls when looking for name locations.
Resolves rdar://problem/35255644.
Adds support for renaming subscripts with external names, e.g.
subscript(x y: Int), and introduces a noncollapsible parameter name range for
subscript parameters, since these shouldn't be collapsed with an argument label
of the same name as function parameter names are.
* [IDE] Refactoring: conversion from “force try” do error handled version
* Removed unnecessary empty line
* Changed name of the refactor
* Review fixes
* Fixed recognizing try_! location by CursorResolver
* Review fixes
