https://github.com/ruby/syntax_suggest/commit/ce7b87184e

https://github.com/ruby/syntax_suggest/commit/ea73ed586a

In #225 it was reported that the output looks incorrect:

```
$ cat /tmp/4a71c7e417cc9eac0971e3a2519b295c/scratch.rb
def x.y.z
end
$ ruby /tmp/4a71c7e417cc9eac0971e3a2519b295c/scratch.rb
/tmp/4a71c7e417cc9eac0971e3a2519b295c/scratch.rb: --> /tmp/4a71c7e417cc9eac0971e3a2519b295c/scratch.rb
expected a delimiter to close the parametersunexpected '.', ignoring it
> 1  def x.y.z
> 2  end
```

Specifically:

```
expected a delimiter to close the parametersunexpected '.', ignoring it
```

However this does not show up when executing the debug executable:

```
$ bin/bundle exec exe/syntax_suggest /tmp/4a71c7e417cc9eac0971e3a2519b295c/scratch.rb
--> /tmp/4a71c7e417cc9eac0971e3a2519b295c/scratch.rb

expected a delimiter to close the parameters
unexpected '.', ignoring it

> 1  def x.y.z
> 2  end
```

This is because `exe/syntax_suggest` uses STDOUT.puts while calling `ruby` with the filename uses a fake IO object represented by MiniStringIO. This class was incorrectly not adding a newline to the end of the print.

The fix was to move the class to it's own file where it can be tested and then fix the behavior.

close https://github.com/ruby/syntax_suggest/pull/225

https://github.com/ruby/syntax_suggest/commit/d2ecd94a3b

Co-authored-by: Andy Yong <andyywz@gmail.com>

Method#unbind clones the method entry, preserving its defined_class.
For methods mixed in via include/extend, defined_class is an ICLASS,
causing UnboundMethod#== to return false when comparing against the
same method obtained via Module#instance_method.

Resolve ICLASS defined_class in method_eq.

[Bug #21873]

	[PATCH] [Bug #21666] Get rid of use of unspecified values

	ruby2_keywords warnings: Quote non-UTF8 method names fully

	It used to quote only part of the method name because NUL byte in
	the method terminates the C string:

	```
	(irb)> "abcdef".encode("UTF-16LE").bytes
	=> [97, 0, 98, 0, 99, 0, 100, 0, 101, 0, 102, 0]
	```

	```
	expected: /abcdef/
	actual: warning: Skipping set of ruby2_keywords flag for a (method not defined in Ruby)\n".
	```

	Do not respect ruby2_keywords on method/proc with post arguments

	Previously, ruby2_keywords could be used on a method or proc with
	post arguments, but I don't think the behavior is desired:

	```ruby
	def a(*c, **kw) [c, kw] end
	def b(*a, b) a(*a, b) end
	ruby2_keywords(:b)

	b({foo: 1}, bar: 1)
	```

	This changes ruby2_keywords to emit a warning and not set the
	flag on a method/proc with post arguments.

	While here, fix the ruby2_keywords specs for warnings, since they
	weren't testing what they should be testing.  They all warned
	because the method didn't accept a rest argument, not because it
	accepted a keyword or keyword rest argument.