fix(ui): cannot redo and undo

app/src/main/java/org/autojs/autojs/ui/edit/editor/CodeEditor.java

@@ -144,7 +144,7 @@ public class CodeEditor extends HVScrollView {
     }
 
     public boolean canUndo() {
-        return mTextViewRedoUndo.canRedo();
+        return mTextViewRedoUndo.canUndo();
     }
 
     public boolean canRedo() {

app/src/main/java/org/autojs/autojs/ui/edit/editor/TextViewUndoRedo.java

@@ -419,6 +419,9 @@ public class TextViewUndoRedo {
         }
 
         public void afterTextChanged(Editable s) {
+            if (mIsUndoOrRedo || !mEnabled) {
+                return;
+            }
             if (mEditHistory.size() < mInitialHistoryStackSize) {
                 mInitialHistoryStackSize = 0;
             }

app/src/main/java/org/autojs/autojs/ui/edit/toolbar/DebugToolbarFragment.java

@@ -111,10 +111,10 @@ public class DebugToolbarFragment extends ToolbarFragment implements DebugCallba
             return;
         }
         CodeEditor editor = mEditorView.getEditor();
-        editor.setRedoUndoEnabled(true);
         if (!TextUtils.equals(mInitialEditorSourceUrl, mCurrentEditorSourceUrl)) {
             editor.setText(mInitialEditorSource);
         }
+        editor.setRedoUndoEnabled(true);
         DebugBar debugBar = mEditorView.getDebugBar();
         debugBar.setTitle(null);
         debugBar.setCodeEvaluator(null);