Strip trailing whitespace on Save with …callbacks!

Open the bundle editor (⌃⌥⌘B) and open "Text" → "Menu Actions" → "Converting / Stripping" → "Remove Trailing Spaces in Document / Selection". Then in the drawer put **callback.document.export** in Semantic Class and **Document** / **Replace Document** as Input / Output. Hooray! From now on each time you'll save a document all trailing space will be stripped!