Update CodeMirror Documentation

I wish I could have added tiddlers to the documentation in order to put the mini-tutorials in tabs but I couldn't.
So it is a bit messy in my opinion, but I think it is a good start.

I have tested every configuration with Tiddlywiki v 5.1.4.
Bootstrap fr-FR edition with a few dozens of translated tiddlers
fr-FR-server configured to serve the fr-FR edition
Integration of @evolena work into the fr-FR edition
Doc: How to Add A Menu to the Sidebar

This item is tagged so as to appear under Customise TiddlyWiki.
Transcluding information re Sidebar Menus

Transcluding information from newly proposed tiddler "How to Add A Menu to the Sidebar". This should help users discover ways in which to use the TOC macro.
Merge remote-tracking branch 'upstream/master' into fred
Allow whitespace after \end in macro definitions

Fixes #1090
Add direct links to resource tiddlers
Reinstate translation for "download full wiki"

It’s used in `$:/snippets/download-wiki-button`
Fix problem with page controls

By transcluding the page controls we were changing the current tiddler
Update docs
Fix wrapping of tags in tag manager

Now long tags wrap onto multiple lines. I think they look quite good,
and we may want to consider using the same technique in the view
template.
Fix problem with cloning tiddlers

We were ignoring the tags on the template tiddler.

Fixes #1097
Add Jed's game to the examples
new buttons, exporter texts
Overriding of a few system tiddlers for fr-FR edition
Various updates to doc tiddlers in fr-FR edition
Corrections to overriden system tiddlers in fr-FR edition
plus new translated tiddlers
Create Page and tiddler layout customisation.tid