[ruby/syntax_suggest] Do not output "Syntax OK" when there's an error

Due to a problem with ripper we do not recognize `break` as invalid code. It's confusing that "Syntax OK" is output in that case.

When there's no syntax error, the algorithm should not say anything. The exception is in the CLI and that's for compatibility with `ruby -wc`

```
$ cat /tmp/break.rb
break
⛄️ 3.1.2 🚀 /Users/rschneeman/Documents/projects/syntax_suggest (schneems/no-syntax-not-okay-break)
$ ruby -wc /tmp/break.rb
Syntax OK
```

> Note that this is invalid, running this code will raise a Syntax error.

```
$ exe/syntax_suggest /tmp/break.rb
Syntax OK
```

Close https://github.com/ruby/syntax_suggest/pull/157

https://github.com/ruby/syntax_suggest/commit/d7bd8f03a2

lib/syntax_suggest/cli.rb

@@ -65,6 +65,7 @@ module SyntaxSuggest
       )
 
       if display.document_ok?
+        @io.puts "Syntax OK"
         @exit_obj.exit(0)
       else
         @exit_obj.exit(1)

lib/syntax_suggest/display_invalid_blocks.rb

@@ -23,7 +23,6 @@ module SyntaxSuggest
 
     def call
       if document_ok?
-        @io.puts "Syntax OK"
         return self
       end
 

spec/syntax_suggest/unit/api_spec.rb

@@ -25,7 +25,7 @@ module SyntaxSuggest
         io: io
       )
 
-      expect(io.string.strip).to eq("Syntax OK")
+      expect(io.string.strip).to eq("")
     end
 
     it "raises original error with warning if a non-syntax error is passed" do

spec/syntax_suggest/unit/display_invalid_blocks_spec.rb

@@ -25,7 +25,7 @@ module SyntaxSuggest
         code_lines: search.code_lines
       )
       display.call
-      expect(io.string).to include("Syntax OK")
+      expect(io.string).to include("")
     end
 
     it "selectively prints to terminal if input is a tty by default" do