docs(form): add submit event detail - prevent default behaviour

Author: dolymood

document/components/docs/en-US/form.md

@@ -443,7 +443,7 @@ CubeForm is a schema-based form generator component.
 
 | Event Name | Description | Parameters 1 | Parameters 2 |
 | - | - | - | - |
-| submit | Form submit, only trigged when the form's validation is ok | e - event | form model value |
+| submit | Form submit, only trigged when the form's validation is ok. If only have sync validators, this event will not be prevented by default. If have async validators, this event will be prevented by default. | e - event | form model value |
 | reset | Form reset | e - event | - |
 | validate | Form validated | Properties: <br>{<br>validity,<br> valid,<br> invalid,<br> dirty,<br> firstInvalidFieldIndex<br>} | - |
 | valid | Form valid | Validity result | - |

document/components/docs/zh-CN/form.md

@@ -443,7 +443,7 @@
 
 | 事件名 | 说明 | 参数1 | 参数2 |
 | - | - | - | - |
-| submit | 表单校验通过后触发此事件 | e - 事件对象 | model 值 |
+| submit | 表单校验通过后触发此事件，如果只有同步校验，则不会阻止默认行为，而如果包含了异步校验，则默认就会阻止默认行为 | e - 事件对象 | model 值 |
 | reset | 表单重置事件 | e - 事件对象 | - |
 | validate | 表单校验事件 | 参数结构如下：<br>{<br>validity,<br> valid,<br> invalid,<br> dirty,<br> firstInvalidFieldIndex<br>} | - |
 | valid | 表单校验成功触发 | validity 校验结果 | - |