修复添加文字进行撤销后， 恢复时的光标问题(fixed qinci#2)

Author: qinci

lib/src/main/java/ren/qinc/edit/PerformEdit.java

@@ -110,7 +110,11 @@ public final void redo() {
         if (action.isAdd) {
             //恢复添加
             editable.insert(action.startCursor, action.actionTarget);
-            editText.setSelection(action.startCursor, action.endCursor);
+            if (action.endCursor == action.startCursor) {
+                editText.setSelection(action.startCursor + action.actionTarget.length());
+            } else {
+                editText.setSelection(action.startCursor, action.endCursor);
+            }
         } else {
             //恢复删除
             editable.delete(action.startCursor, action.startCursor + action.actionTarget.length());