add `function`

`add(line, curData, scope, docMap)`

Tag.add for @constructor. Sets this.type to "constructor".

Also sets this.name and this.title using bit-docs-type-annotate.

Parameters

line {String}:
Text from @constructor until the end of line.

For example:
```
@constructor my-project/lib/index
```

curData {DocObject}:

DocObject for the block.

For example:

{
  src: {
    path: 'lib/index.js'
  },
  body: '',
  description: '',
  parent: 'my-project/lib'
}

scope {DocObject}:
DocObject representing current scope.

For example:
```
{
  type: 'script',
  name: 'lib/index.js'
}
```
docMap {DocMap}:
DocMap being added to.

Returns

{ProcessTagsCommand}:

['scope', this].