Style: Fix code format scripts compat with non-GNU Unices

It's too hard to get compatibility between GNU and BSD sed,
so let's just use perl oneliners.

And improve it to also remove trailing tabs, not just spaces.

doc/classes/EditorTranslationParserPlugin.xml

@@ -35,7 +35,7 @@
 
 
 		func get_recognized_extensions():
-		    return ["gd"]			
+		    return ["gd"]
 		[/codeblock]
 	</description>
 	<tutorials>