Docs: Improved keywords and the readme. [skip ci]

package.json

@@ -4,14 +4,11 @@
   "description": "The document editor build of CKEditor 5 – the best browser-based rich text editor.",
   "keywords": [
     "ckeditor5-build",
-    "CKEditor",
+    "ckeditor",
     "ckeditor5",
     "ckeditor 5",
-    "WYSIWYG",
-    "WYSIWYM",
-    "text",
-    "rich-text",
-    "richtext",
+    "wysiwyg",
+    "rich text",
     "editor",
     "html",
     "contentEditable",
@@ -21,7 +18,6 @@
     "collaboration",
     "collaborative",
     "real-time",
-    "virtual dom",
     "framework"
   ],
   "main": "./build/ckeditor.js",