Add documentation for {module_path} placeholder

Per arthanson's review request, updated docs/models/dcim/moduletype.md
to document:
- {module} placeholder behavior (single vs multiple use)
- {module_path} placeholder for full path expansion
- Position field resolution for nested module bays

docs/models/dcim/moduletype.md

@@ -16,9 +16,33 @@ Note that device bays and module bays may _not_ be added to modules.
 
 ## Automatic Component Renaming
 
-When adding component templates to a module type, the string `{module}` can be used to reference the `position` field of the module bay into which an instance of the module type is being installed.
+When adding component templates to a module type, placeholders can be used to dynamically incorporate the module bay's `position` field into component names. Two placeholders are available:
 
-For example, you can create a module type with interface templates named `Gi{module}/0/[1-48]`. When a new module of this type is "installed" to a module bay with a position of "3", NetBox will automatically name these interfaces `Gi3/0/[1-48]`.
+### `{module}` Placeholder
+
+The `{module}` placeholder references the position of the parent module bay:
+
+* **Single use**: Expands to the immediate parent's position only
+* **Multiple uses**: Each `{module}` token is replaced level-by-level (the number of tokens must match the nesting depth)
+
+For example, a module type with interface templates named `Gi{module}/0/[1-48]`, when installed in a module bay with position "3", will create interfaces named `Gi3/0/[1-48]`.
+
+### `{module_path}` Placeholder
+
+The `{module_path}` placeholder expands to the full path from the root device to the current module, with positions joined by `/`. This is useful for modules that can be installed at any nesting depth without modification.
+
+For example, consider an SFP module type with an interface template named `eth{module_path}`:
+
+* Installed directly in slot 2: creates interface `eth2`
+* Installed in slot 1's nested bay 1: creates interface `eth1/1`
+* Installed in slot 1's nested bay 2's sub-bay 3: creates interface `eth1/2/3`
+
+!!! note
+    `{module_path}` can only be used once per template attribute, and cannot be mixed with `{module}` in the same attribute.
+
+### Position Field Resolution
+
+The `{module}` placeholder can also be used in the `position` field of [module bay templates](./modulebaytemplate.md) defined on a module type. This allows nested module bays to build hierarchical position values. For example, a module bay template with `position="{module}/1"`, when its parent module is installed in a bay with position "2", will have its position resolved to "2/1".
 
 Automatic renaming is supported for all modular component types (those listed above).