fix(boards): 修复skulpt turtle下stamp方法报错

boards/default_src/python_skulpt/blocks/turtle.js

@@ -875,3 +875,15 @@ export const turtle_screen_savefig = {
     }
 };
 
+export const turtle_stamp = {
+    init: function () {
+        this.setColour(TURTLE_HUE);
+        this.appendValueInput('TUR')
+            .setCheck('Turtle')
+        this.appendDummyInput()
+            .appendField(Blockly.Msg.TURTLE_STAMP);
+        this.setInputsInline(true);
+        this.setPreviousStatement(true);
+        this.setNextStatement(true);
+    }
+};

boards/default_src/python_skulpt/generators/turtle.js

@@ -381,4 +381,11 @@ export const turtle_screen_savefig = function (_, generator) {
     var file = generator.valueToCode(this, 'FILE', generator.ORDER_ATOMIC);
     var code = varName + ".getcanvas().postscript(file=" + file + ")\n";
     return code;
+}
+
+export const turtle_stamp = function (_, generator) {
+    generator.definitions_.import_turtle = "import turtle";
+    var varName = generator.valueToCode(this, 'TUR', generator.ORDER_ASSIGNMENT) || '0';
+    var code = varName + '.stamp()\n';
+    return code;
 }