Merge pull request #3509 from Calinou/remove-editor-dev-intro-page

Remove uninformative editor development Introduction page

development/editor/index.rst

@@ -5,5 +5,4 @@ Editor development
    :maxdepth: 1
    :name: toc-devel-editor
 
-   introduction
    creating_icons

development/editor/introduction.rst

@@ -1,9 +0,0 @@
-.. _doc_editor_intro:
-
-Introduction
-============
-
-As the engine is constantly evolving and new features are being added, it is
-important to familiarize yourself with the editor and tools development in C++.
-Without the editor, some of the engine's internal functionality would become
-unaccessible and make the development not intuitive.