update setters and docs

packages/slate/src/models/range.js

@@ -763,6 +763,18 @@ class Range extends Record(DEFAULTS) {
     return range
   }
 
+  /**
+   * Set the `isAtomic` property to a new `value`.
+   *
+   * @param {Boolean} value
+   * @return {Range}
+   */
+
+  setIsAtomic(value) {
+    const range = this.set('isAtomic', value)
+    return range
+  }
+
   /**
    * Set the `isFocused` property to a new `value`.
    *
@@ -775,6 +787,18 @@ class Range extends Record(DEFAULTS) {
     return range
   }
 
+  /**
+   * Set the `marks` property to a new set of `marks`.
+   *
+   * @param {Set} marks
+   * @return {Range}
+   */
+
+  setMarks(marks) {
+    const range = this.set('marks', marks)
+    return range
+  }
+
   /**
    * Set the anchor and focus points to new `values`.
    *