Fixes require for generated reference examples.

Update example.md.twig

Author: Vincent (Wen Yu) Ge

templates/ruby/docs/example.md.twig

@@ -1,4 +1,4 @@
-require '{{ spec.title }}'
+require '{{ spec.title | lower }}'
 
 include {{ spec.title | caseUcfirst }}
 
@@ -14,4 +14,4 @@ client = Client.new
 
 response = {{ service.name | caseSnake }}.{{ method.name | caseSnake }}({% for parameter in method.parameters.all %}{% if parameter.required %}{% if not loop.first %}, {% endif %}{{parameter.name|caseSnake}}: {% if parameter.type == 'file' %}{{ parameter | paramExample }}{% else %}{{ parameter | paramExample }}{% endif %}{% endif %}{% endfor %})
 
-puts response.inspect
+puts response.inspect