Indention in the fields's comments is not preserved in the generated document

For example, the comment in the field is like the following

```

// Policy defines user-defined RBAC policies and role definitions in CSV format.
// Example:
//
// policy: |
// p, role:devops, applications, *, */*, allow
// p, role:devops, clusters, get, *, allow
// g, Alice, role:devops
// g, Bob, role:admin
//
Policy string `json:"policy,omitempty"`

```

but in the generated document, the indentions are all missing, the result is like

```
Policy defines user-defined RBAC policies and role definitions in CSV format.

Example:

policy: |
p, role:devops, applications, , */, allow
p, role:devops, clusters, get, *, allow
g, Alice, role:devops
g, Bob, role:admin
```

Is it possible to preserve the indention? Thanks