Component description is not being generated when using class-style components

[tomvanoosterwyck]

Describe the bug
Component description is not being generated when using class-style components

To Reproduce
Steps to reproduce the behavior:
1: Component:

<script lang="ts">
import Vue from 'vue'
import Component from 'vue-class-component'
import { Prop } from 'vue-property-decorator'

@Component({
  // ...
})
/**
 * @group GroupA
 * This is a description of the component
 */
export default class Child extends Vue {
  @Prop(Object) readonly propA: any
}
</script>

2: vuese gen

3:
Output:

# Child

## Props

<!-- @vuese:Child:props:start -->
|Name|Description|Type|Required|Default|
|---|---|---|---|---|
|propA|-|`Object`|`false`|-|

<!-- @vuese:Child:props:end -->

Expected behavior

# Child
This is a description of the component
## Props

<!-- @vuese:Child:props:start -->
|Name|Description|Type|Required|Default|
|---|---|---|---|---|
|propA|-|`Object`|`false`|-|

<!-- @vuese:Child:props:end -->

Environmental information:

vuese --version
1.4.7

System:

OS: Win 10 Pro Version 1903
Binaries:
Node: v12.18.2
Yarn: 1.22.4
npm: 6.14.5

Additional information
none