Remove UndoManager stuff from AStyle

The only change that happens is a single `setText()` call, which already
results in a single undo action.

Author: matthijskooijman

app/src/cc/arduino/packages/formatter/AStyle.java

@@ -91,10 +91,8 @@ public void run() {
     int line = getLineOfOffset(textArea);
     int lineOffset = getLineOffset(textArea, line);
 
-    textArea.getUndoManager().beginInternalAtomicEdit();
     editor.removeAllLineHighlights();
     editor.getCurrentTab().setText(formattedText);
-    textArea.getUndoManager().endInternalAtomicEdit();
 
     if (line != -1 && lineOffset != -1) {
       try {