[Fix rubocop#6566] Fix a false positive for `Layout/EmptyLinesAroundA…

…ccessModifier`

Fixes rubocop#6566.

This PR fixes a false positive for `Layout/EmptyLinesAroundAccessModifier`
when at the end of specifying a superclass is missing blank line.

The following is originally no offense code.
(It is probably a regression by rubocop#6307)

```console
% cat example.rb
class SomeController < SomeOtherController
  def index; end

  private
end

% rubocop example.rb --only Layout/EmptyLinesAroundAccessModifier -a
Inspecting 1 file
C

Offenses:

example.rb:4:3: C: [Corrected] Layout/EmptyLinesAroundAccessModifier:
Keep a blank line before and after private.
  private
  ^^^^^^^

1 file inspected, 1 offense detected, 1 offense corrected
```

Auto-correct adds a blank line after `private`. This is due to false positives.

```diff
 % cat example.rb
 class SomeController < SomeOtherController
   def index; end

   private
+
 end
```

This caused the infinite loop in `Layout/EmptyLinesAroundAccessModifier` and
`Layout/EmptyLinesAroundClassBody`.

```console
% rubocop example.rb --only Layout/EmptyLinesAroundClassBody -a
Inspecting 1 file
C

Offenses:

example.rb:5:1: C: [Corrected] Layout/EmptyLinesAroundClassBody: Extra
empty line detected at class body end.

1 file inspected, 1 offense detected, 1 offense corrected
```

Auto-correct removes the blank line from after of `private`.

```diff
 % cat example.rb
 class SomeController < SomeOtherController
   def index; end

   private
-
 end
```

It loops to the first code. This PR fixes the infinite loop.

CHANGELOG.md

@@ -91,6 +91,7 @@
 * [#6533](https://github.com/rubocop-hq/rubocop/issues/6533): Improved warning message for unrecognized cop parameters to include Supported parameters. ([@MagedMilad][])
 * [#6389](https://github.com/rubocop-hq/rubocop/pull/6389): Fix false negative for `Style/TrailingCommaInHashLitera`/`Style/TrailingCommaInArrayLiteral` when there is a comment in the last line. ([@bayandin][])
 * [#6343](https://github.com/rubocop-hq/rubocop/pull/6343): Optimise `--auto-gen-config` when `Metrics/LineLength` cop is disabled. ([@tom-lord][])
+* [#6566](https://github.com/rubocop-hq/rubocop/issues/6566): Fix false positive for `Layout/EmptyLinesAroundAccessModifier` when at the end of specifying a superclass is missing blank line. ([@koic][])
 
 ## 0.61.1 (2018-12-06)