Refs #3809 - Remove rubocop TODOs

Removed the following TODOs so that cops for these will run from now on:

Lint/AmbiguousOperator, DefEndAlignment, DeprecatedClassMethods
EnsureReturn, RequireParentheses, Void, BlockAlignment, EndAlignment,
UselessAccessModifier,

Style/IndentArray, IndentHash, Tab, UnlessElse, UnneededPercentQ, UnneededPercentX, RedundantReturn

Rails/Validation
This one in particular is fixing 
```ruby
# C: Use 2 spaces for indentation in a hash, relative to the start of the line where the left curly brace is.
                                   :snippet  => false,
#                                 ^^^^^^^^^^^^^^^^^^
# C: Indent the right brace the same as the start of the line where the left brace is.
                              }.merge(input))
```