Added quick reference section for adding unicode characters

Mainly using unicode characters in the content of my books/guides to represent
keyboard characters, such as arrow keys.  It is assumed that these unicode
characters make the keybindings easier to understand.

SUMMARY.md

@@ -174,6 +174,7 @@
     * [Local Assignment](reference/local-assignement.md)
 * [Misc](misc/index.md)
     * [Artist mode](misc/artist-mode.md)
+    * [Unicode Characters](misc/unicode-characters.md)
 * [Contributors](contributors.md)
 * [About this workshop](introduction/about-this-workshop.md)
     * [Workshop conventions](introduction/workshop-conventions.md)

misc/unicode-characters.md

@@ -0,0 +1,19 @@
+# Unicode Characters
+
+`SPC i u` shows a pop-up list of [Unicode characters](https://en.wikipedia.org/wiki/Universal_Coded_Character_Set) by name, with each name also showing the unicode character.
+
+The first time `SPC i u` is called the unicode characters are loaded, as spacemacs doesnt load them in by default.  Loading should only take a second.
+
+As the popup list can be narrowed by typing part or all of the name of characters.  The list shows a fuzzy match of unicode names that match.
+
+| Keybindings | Description                                                                      |
+|-------------|----------------------------------------------------------------------------------|
+| `SPC i u`   | Loads unicode characters and lists them in a popup window.  Uses helm completion |
+
+
+[![Spacemacs Unicode Characters](/images/spacemacs-unicode-popup.png)](/images/spacemacs-unicode-popup.png)
+
+
+## Classic Emacs Unicode 8
+
+`C-c 8 RET` is the classic way to add Unicode 8 characters, which seems to show different symbols, is that unicode 8 and the other unicode 16 perhaps?