Update generator Project config docs

configuration/project.md

@@ -414,6 +414,71 @@ footer:
 
 ## generator
 
+### directoryIndex
+
+Configuration options to instruct Retype on how and when to deal with the default directory index files, such as `index.html`.
+
+### directoryIndex.altNames
+
+=== directoryIndex.altNames : `list`
+A list of alternative default HTML document file names.
+
+By default, Retype uses the following list of `altNames`:
+
+```yml
+generator:
+  directoryIndex:
+    altNames:
+      - index.html
+      - index.htm
+      - default.html
+      - default.htm
+```
+===
+
+### directoryIndex.append
+
+=== directoryIndex.append : `boolean`
+Specifies if the default document file name should be appended to resolved URLs. By default, Retype does not append the default file name.
+
+If `false`, the generated link will be `/guide/`. If `true`, the generated link will be `/guides/index.html`.
+
+```yml
+generator:
+  directoryIndex:
+    append: true # default is false
+```
+===
+
+### directoryIndex.name
+
+=== directoryIndex.name : `string`
+The default HTML document file name generated by Retype.
+
+```yml
+generator:
+  directoryIndex:
+    name: default.htm # Default is index.html
+```
+===
+
+### paths
+
+=== paths : `string`
+Configures url kind preference for resolved urls. Supported values: `source`, `relative`, and `root`.
+
+Option | Description
+---    | ---
+`relative` | Link paths are constructed using relative paths. Example: `../../guide/introduction/`. This is the default.
+`root`     | Link paths are constructed using paths resolving to the website root. Example: `/guide/introduction/`
+`source`   | Link paths are constructed using paths resolving to the source file root.
+
+```yml
+generator:
+  paths: relative
+```
+===
+
 ### recase
 
 === recase : `string`