bug#54702: 29.0.50; ruby-mode indentation: endless methods

[Aaron Jensen <aaronjensen@gmail.com>]

Ruby 3 and 3.1 bring us different versions of endless methods. They
currently don't indent correctly in `ruby-mode`:

Current:

```rb
class Bar
  def foo = bar

    def baz
    end
  end
```

Expected:

```rb
class Bar
  def foo = bar

  def baz
  end
end
```
In GNU Emacs 29.0.50 (build 1, aarch64-apple-darwin21.3.0, NS appkit-2113.30 Version 12.2.1 (Build 21D62))
 of 2022-03-04 built on aaron-m1.local
Windowing system distributor 'Apple', version 10.3.2113
System Description:  macOS 12.3.1

Configured using:
 'configure --disable-dependency-tracking --disable-silent-rules
 --enable-locallisppath=/opt/homebrew/share/emacs/site-lisp
 --infodir=/opt/homebrew/Cellar/emacs-plus@29/29.0.50/share/info/emacs
 --prefix=/opt/homebrew/Cellar/emacs-plus@29/29.0.50 --with-xml2
 --with-gnutls --with-native-compilation --without-dbus
 --without-imagemagick --with-modules --with-rsvg --with-ns
 --disable-ns-self-contained 'CFLAGS=-I/opt/homebrew/opt/gcc/include
 -I/opt/homebrew/opt/libgccjit/include -I/opt/homebrew/opt/gmp/include
 -I/opt/homebrew/opt/jpeg/include' 'LDFLAGS=-L/opt/homebrew/lib/gcc/11
 -I/opt/homebrew/opt/gcc/include -I/opt/homebrew/opt/libgccjit/include
 -I/opt/homebrew/opt/gmp/include -I/opt/homebrew/opt/jpeg/include''

Configured features:
ACL GIF GLIB GMP GNUTLS JPEG JSON LCMS2 LIBXML2 MODULES NATIVE_COMP
NOTIFY KQUEUE NS PDUMPER PNG RSVG SQLITE3 THREADS TIFF
TOOLKIT_SCROLL_BARS XIM ZLIB

Important settings:
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix