chore(markdown): Linting of dev docs

markdown/dev/reference/api/attributes/add/en.md

@@ -8,7 +8,7 @@ Attributes attributes.add(string key, string value)
 
 Adds `value` to the attribute identified by `key`.
 
-Adding multiple values to the same key will result in them being joined together 
+Adding multiple values to the same key will result in them being joined together
 (with a space) when rendering.
 
 ```js
@@ -28,4 +28,3 @@ paths.demo = new Path()
 paths.demo = new Path()
   .attr('class', 'classA classB');
 ```
-

markdown/dev/reference/api/attributes/clone/en.md

@@ -17,4 +17,3 @@ paths.demo = new Path()
 
 paths.clone = paths.demo.clone()
 ```
-

markdown/dev/reference/api/attributes/en.md

@@ -6,7 +6,7 @@ order: 40
 Attributes is an object that holds attributes for a variety of other objects.
 
 Attributes are attached to [`Point`](/reference/api/point), [`Path`](/reference/api/path), and [`Snippet`](/reference/api/snippet) objects,
-as well as the internal [`Svg`](/reference/api/svg) object. 
+as well as the internal [`Svg`](/reference/api/svg) object.
 
 All of these have an instantiated Attributes object in their `attributes` property.
 

markdown/dev/reference/api/attributes/getasarray/en.md

@@ -18,4 +18,3 @@ paths.demo = new Path()
 let class = paths.demo.attributes.getAsArray('class'); 
 // class now holds: ["classA", "classB"]
 ```
-