Plug-in breaks hyperlink detection in class files

[gdethier]

With version 0.4.1, hyperlink detection is broken in class files. The following error message is shown in Eclipse error log:

java.lang.ClassCastException: class org.eclipse.jdt.internal.ui.javaeditor.InternalClassFileEditorInput cannot be cast to class org.eclipse.ui.IFileEditorInput (org.eclipse.jdt.internal.ui.javaeditor.InternalClassFileEditorInput is in unnamed module of loader org.eclipse.osgi.internal.loader.EquinoxClassLoader @e8bd42f; org.eclipse.ui.IFileEditorInput is in unnamed module of loader org.eclipse.osgi.internal.loader.EquinoxClassLoader @660b1a9d)
	at poussecafe.eclipse.plugin.hyperlink.MessageListenerHyperlinkDetector.editedFile(MessageListenerHyperlinkDetector.java:63)
	at poussecafe.eclipse.plugin.hyperlink.MessageListenerHyperlinkDetector.isEligibleContent(MessageListenerHyperlinkDetector.java:58)
	at poussecafe.eclipse.plugin.hyperlink.MessageListenerHyperlinkDetector.detectHyperlinks(MessageListenerHyperlinkDetector.java:43)