ScriptHeader: move default method impl to iface

Author: ctrueden

src/main/java/org/scijava/script/AbstractScriptHeader.java

@@ -49,11 +49,6 @@ public boolean supports(final ScriptLanguage language) {
 		return language != null && language.getClass() == handledType();
 	}
 
-	@Override
-	public Class<ScriptLanguage> getType() {
-		return ScriptLanguage.class;
-	}
-
 	// -- Internal methods --
 
 	protected abstract Class<? extends ScriptLanguage> handledType();

src/main/java/org/scijava/script/ScriptHeader.java

@@ -45,4 +45,11 @@ public interface ScriptHeader extends HandlerPlugin<ScriptLanguage> {
 	 * @return The header text for scripts of the supported language.
 	 */
 	String getHeader();
+
+	// -- Typed methods --
+
+	@Override
+	default Class<ScriptLanguage> getType() {
+		return ScriptLanguage.class;
+	}
 }