Automatic table of contents generation for Markdown

Adds table of contents for any Markdown note or
Markdown snippet.
Consequent generations update existing TOC.
Generated TOC is case sensitive to handle #2067

Shortcut : CommandOrControl+Alt+T
Menu : Edit/Generate/Update Markdown TOC

webpack-skeleton.js

@@ -37,6 +37,7 @@ var config = {
     'markdown-it-kbd',
     'markdown-it-plantuml',
     'markdown-it-admonition',
+    'markdown-toc',
     'devtron',
     '@rokt33r/season',
     {