Update spec.md (#247)

Author: joshspicer

_implementors/spec.md

@@ -63,7 +63,7 @@ The metadata is added to the image as a `devcontainer.metadata` label with a JSO
 
 To apply the metadata together with a user's devcontainer.json at runtime, the following merge logic by property is used. The table also notes which properties are currently supported coming from the devcontainer.json and from the Feature metadata- this will change over time as we add more properties.
 
-| Property | Type/Format | Merge Logic | devcontainer.json | Feature Metadata |
+| Property | Type/Format | Merge Logic | devcontainer.json | devcontainer-feature.json |
 | -------- | ----------- | ----------- | :---------------: | :--------------: |
 | `id` | E.g., `ghcr.io/devcontainers/features/node:1` | Not merged. |   | x |
 | `init` | `boolean` | `true` if at least one is `true`, `false` otherwise. | x | x |