syntax_suggest did not work great when there is no new line at the end
of the input file.
Input:
```
def foo
end
end # No newline at end of file
```
Previous output:
```
$ ruby test.rb
test.rb: --> test.rb
Unmatched `end', missing keyword (`do', `def`, `if`, etc.) ?
> 1 def foo
> 2 end
> 3 end # No newline at end of filetest.rb:3: syntax error, unexpected `end' (SyntaxError)
end # No newline at end of file
^~~
```
Note that "test.rb:3: ..." is appended to the last line of the
annotation.
This change makes sure that the annotation ends with a new line.
New output:
```
$ ruby test.rb
test.rb: --> test.rb
Unmatched `end', missing keyword (`do', `def`, `if`, etc.) ?
> 1 def foo
> 2 end
> 3 end # No newline at end of file
test.rb:3: syntax error, unexpected `end' (SyntaxError)
end # No newline at end of file
^~~
```
https://github.com/ruby/syntax_suggest/commit/db4cf9147d
d511e6960f