bbatsov/rubocop

### New features

* [#5881](https://github.com/rubocop/rubocop/pull/5881): Add new `Rails/BulkChangeTable` cop. ([@wata727][])
* [#5444](https://github.com/rubocop/rubocop/pull/5444): Add new `Style/AccessModifierDeclarations` cop. ([@brandonweiss][])
* [#5803](https://github.com/rubocop/rubocop/issues/5803): Add new `Style/UnneededCondition` cop. ([@balbesina][])
* [#5406](https://github.com/rubocop/rubocop/issues/5406): Add new `Layout/ClosingHeredocIndentation` cop. ([@siggymcfried][])
* [#5823](https://github.com/rubocop/rubocop/issues/5823): Add new `slashes` style to `Rails/FilePath` since Ruby accepts forward slashes even on Windows. ([@sunny][])
* New cop `Layout/LeadingBlankLines` checks for empty lines at the beginning of a file. ([@rrosenblum][])

### Bug fixes

* [#5897](https://github.com/rubocop/rubocop/issues/5897): Fix `Style/SymbolArray` and `Style/WordArray` not working on arrays of size 1. ([@TikiTDO][])
* [#5894](https://github.com/rubocop/rubocop/pull/5894): Fix `Rails/AssertNot` to allow it to have failure message. ([@koic][])
* [#5888](https://github.com/rubocop/rubocop/issues/5888): Do not register an offense for `headers` or `env` keyword arguments in `Rails/HttpPositionalArguments`. ([@rrosenblum][])
* Fix the indentation of autocorrected closing squiggly heredocs. ([@garettarrowood][])
* [#5908](https://github.com/rubocop/rubocop/pull/5908): Fix `Style/BracesAroundHashParameters` auto-correct going past the end of the file when the closing curly brace is on the last line of a file. ([@EiNSTeiN-][])
* Fix a bug where `Style/FrozenStringLiteralComment` would be added to the second line if the first line is empty. ([@rrosenblum][])
* [#5914](https://github.com/rubocop/rubocop/issues/5914): Make `Layout/SpaceInsideReferenceBrackets` aware of `no_space` when using nested reference brackets. ([@koic][])
* [#5799](https://github.com/rubocop/rubocop/issues/5799): Fix false positive in `Style/MixinGrouping` when method named `include` accepts block. ([@Darhazer][])

### Changes

* [#5937](https://github.com/rubocop/rubocop/pull/5937): Add new `--fix-layout/-x` command line alias. ([@scottmatthewman][])
* [#5887](https://github.com/rubocop/rubocop/issues/5887): Remove `Lint/SplatKeywordArguments` cop. ([@koic][])
* [#5761](https://github.com/rubocop/rubocop/pull/5761): Add `httpdate` to accepted `Rails/TimeZone` methods. ([@cupakromer][])
* [#5899](https://github.com/rubocop/rubocop/pull/5899): Add `xmlschema` to accepted `Rails/TimeZone` methods. ([@koic][])
* [#5906](https://github.com/rubocop/rubocop/pull/5906): Move REPL command from `rake repl` task to `bin/console` command. ([@koic][])
* [#5917](https://github.com/rubocop/rubocop/pull/5917): Let `inherit_mode` work for default configuration too. ([@jonas054][])
* [#5929](https://github.com/rubocop/rubocop/pull/5929): Stop including string extensions from `unicode/display_width`. ([@nroman-stripe][])

[@wata727]: https://github.com/wata727
[@brandonweiss]: https://github.com/brandonweiss
[@balbesina]: https://github.com/balbesina
[@siggymcfried]: https://github.com/siggymcfried
[@sunny]: https://github.com/sunny
[@rrosenblum]: https://github.com/rrosenblum
[@TikiTDO]: https://github.com/TikiTDO
[@koic]: https://github.com/koic
[@garettarrowood]: https://github.com/garettarrowood
[@EiNSTeiN-]: https://github.com/EiNSTeiN-
[@Darhazer]: https://github.com/Darhazer
[@scottmatthewman]: https://github.com/scottmatthewman
[@cupakromer]: https://github.com/cupakromer
[@jonas054]: https://github.com/jonas054
[@nroman-stripe]: https://github.com/nroman-stripe