Summary
    Sets the key to use in the heading documents to store the parent
    of a given heading.
    
		- Assembly
 - Wyam
.Html .dll  - Namespace
 - Wyam
.Html  - Containing Type
 - Headings
 
Syntax
public Headings WithParentKey(string parentKey)
	Parameters
| Name | Type | Description | 
|---|---|---|
| parentKey | string | The key to use for the parent. | 
Return Value
| Type | Description | 
|---|---|
| Headings | The current module instance. | 
