Replaces the hash rocket operator in favor of the newer Ruby syntax on render

[liuriloami]

Summary

Updates the calls to render replacing the hash rocket operator in favor of the new syntax introduced in Ruby 1.9.1 and Ruby 2.2 for code and style consistency.

Other Information

This is a follow up of #43367, trying to update some code that was still using the hash rocket syntax while the majority of the code wasn't.

What I did here was replacing render :([a-z0-9_]+) => by render $1:, while double checking for calls that had more than one param which had to be replaced by hand.

[nvasilevski]

Seems like a reasonable thing to have 👍
Perhaps needs to be rebased

[rafaelfranca]

We don't accept cosmetic changes but I'll open an exception because it is a first time contributor