Simplify Copy button example (jenkinsci#427)

Author: janfaracik

src/main/resources/io/jenkins/plugins/designlibrary/Buttons/index.jelly

@@ -88,7 +88,7 @@ THE SOFTWARE.
     <s:section title="${%copy}" description="${%copy.description}">
       <s:group>
         <s:preview>
-          <l:copyButton message="text copied" text="A shoulder of lemon fields" tooltip="Click to copy" />
+          <l:copyButton text="A shoulder of lemon fields" />
         </s:preview>
         <s:code file="copyButton.jelly" />
       </s:group>

src/main/resources/lib/samples/code.jelly

@@ -33,7 +33,7 @@
             <l:icon src="symbol-open-outline plugin-ionicons-api" />
           </a>
         </j:if>
-        <l:copyButton text="${code}" message="${%Copied}" tooltip="${%Copy code block}" clazz="jenkins-button--tertiary" />
+        <l:copyButton text="${code}" clazz="jenkins-button--tertiary" />
       </div>
     </div>
   </div>

src/main/webapp/Buttons/copyButton.jelly

@@ -1 +1 @@
-<l:copyButton message="text copied" text="A shoulder of lemon fields" tooltip="Click to copy" />
+<l:copyButton text="A shoulder of lemon fields" />