message: docs(copyright2): add docs about canonical
diff: @@ -5,13 +5,6 @@ icon: config
  ## Plugin Options
  -### hostname
  -
  -- Type: `string`
  -- Required: No
  -
  -Deploy hostname
  -
  ### author
  - Type: `string | ((page: Page) => string)`
  @@ -54,6 +47,26 @@ Disable copy
  Disable selection
  +### canonical
  +
  +- Type: `string`
  +- Required: No
  +
  +Canonical hostname with base.
  +
  +This is useful when your content are deploying in multiple places.
  +
  +::: note Example
  +
  +If you are deploying same content under `https://myblog.com` and `https://blog.com/username/`, you may want to prefer one site as reference link.
  +
  +- If you prefer the first one, you should set `canonical` to `https://myblog.com`
  +- If you prefer the second one, you should set `canonical` to `https://blog.com/username/`
  +
  +So copyright message triggered by copying content on another site also points to your preferred site.
  +
  +:::
  +
  ### locales
  - Type: `CopyrightLocaleConfig`
  