Removing dom ID requirement for margin/sidenotes (#10)

* Removing dom ID requirement for margin/sidenotes

Prior to this commit, when using the `marginnote` or `sidenote`
shortcodes, you would need to pass a domId parameter to the shortcode.

With this change you no longer need to pass a parameter, and any
parameter passed is ignored. The pre-amble creates a unique domID for
the shortcodes.

* Replacing convoluted Scratch with Ordinal

I was leveraging the Scratch function of Hugo, when I could instead
rely on `.Ordinal`

README.md

@@ -105,9 +105,8 @@ support all the features present in the
 
 - `marginnote`
   - **Description**: Wrap text to produce a numberless margin note.
-  - Usage: Accepts a required positional argument that is the margin note id.
-  `{{% marginnote "<margin note id>"" %}}...{{% /marginnote %}}`
-  - **Example**: `{{% marginnote "mn-example" %}}Some marginnote{{% /marginnote%}}`
+  - Usage: `{{% marginnote %}}...{{% /marginnote %}}`
+  - **Example**: `{{% marginnote %}}Some marginnote{{% /marginnote%}}`
 
 - `section`
    - **Description**: This shortcode is provided as a work-around for wrapping
@@ -123,10 +122,9 @@ support all the features present in the
 
 - `sidenote`
   - **Description**: Wrap text to produce an automatically numbered sidenote.
-  - **Usage**: identical to `marginnote`. 
-  Accepts a required positional argument that is the side note id.
-  `{{% sidenote "<side note id>"" %}}...{{% /sidenote %}}`
-  - **Example**: `{{% sidenote "sn-example" %}}Some sidenote{{% /sidenote %}}`
+  - **Usage**: identical to `marginnote`
+  `{{% sidenote %}}...{{% /sidenote %}}`
+  - **Example**: `{{% sidenote %}}Some sidenote{{% /sidenote %}}`
 
 
 ## Templates

layouts/shortcodes/marginnote.html

@@ -1,3 +1,3 @@
-<label for="{{ .Get 0 }}" class="margin-toggle">&#8853;</label>
-<input type="checkbox" id="{{ .Get 0 }}" class="margin-toggle"/>
+{{ $marginnoteDomIdSuffix := .Ordinal }}<label for="marginnote-{{.Page.UniqueID}}-{{ $marginnoteDomIdSuffix }}" class="margin-toggle">&#8853;</label>
+<input type="checkbox" id="marginnote-{{.Page.UniqueID}}-{{ $marginnoteDomIdSuffix }}" class="margin-toggle"/>
 <span class="marginnote">{{ .Inner }}</span>

layouts/shortcodes/sidenote.html

@@ -1,3 +1,3 @@
-<label for="{{ .Get "id" }}" class="margin-toggle sidenote-number"></label>
-<input type="checkbox" id="{{ .Get "id" }}" class="margin-toggle"/>
+{{ $sidenoteDomIdSuffix := .Ordinal }}<label for="sidenote-{{.Page.UniqueID}}-{{ $sidenoteDomIdSuffix }}" class="margin-toggle sidenote-number"></label>
+<input type="checkbox" id="sidenote-{{.Page.UniqueID}}-{{ $sidenoteDomIdSuffix }}" class="margin-toggle"/>
 <span class="sidenote">{{ .Inner }}</span>