Rename read-from-element to element-properties

Also update sidbar

docs/element-properties.mdx

@@ -0,0 +1,12 @@
+---
+id: element-properties
+title: Properties of DOM nodes
+---
+
+## Traversal (and ientification)
+
+## Attribute, class, id, data
+
+## Scroll
+
+## Content - html, text

docs/read-from-element.md

@@ -1,4 +0,0 @@
----
-id: read-from-element
-title: Properties of DOM nodes
----

sidebars.js

@@ -2,7 +2,7 @@ module.exports = {
   "Quick Guide": {
     "DOM and Events": [
       "create-modify-element",
-      'read-from-element',
+      'element-properties',
      ],
 
     /*