Update previously used name for Github trigger option

jonespm · web-flow · commit 92a6d3ce47fc · 2020-05-08T16:29:24.000-04:00
This name looks like it was changed from "Build when a change is pushed to GitHub" to "GitHub hook trigger for GITScm polling" a few years ago. However in Configure System under the Github plugin it still has the wrong text when clicking the help button. This confused me today and looks like it's been confusing for a few years now from [Stack Overflow](https://stackoverflow.com/questions/30576881/jenkins-build-when-a-change-is-pushed-to-github-option-is-not-working)
diff --git a/src/main/resources/org/jenkinsci/plugins/github/config/GitHubPluginConfig/help.jelly b/src/main/resources/org/jenkinsci/plugins/github/config/GitHubPluginConfig/help.jelly
@@ -8,7 +8,7 @@
                 This plugin doesn't do anything with the GitHub API unless you add a configuration with credentials.
                 So if you don't want to add any configuration, you can set up hooks for this Jenkins instance manually.
                 <br/>
-                In this mode, in addition to configuring projects with "<i>Build when a change is pushed to GitHub</i>",
+                In this mode, in addition to configuring projects with "<i>GitHub hook trigger for GITScm polling</i>",
                 you need to ensure that Jenkins gets a POST to its
                 <tt><a href="${rootURL}/github-webhook/">${app.rootUrl}github-webhook/</a></tt>.
             </p>
