add syntax-highlighting documentation

modules/syntax-highlighting/README.md

@@ -0,0 +1,18 @@
+Syntax-Highlighting
+===================
+
+Adds fish shell-like [syntax highlighting](https://github.com/zsh-users/zsh-syntax-highlighting) to your shell.
+
+![syntax-highlighting][syntax_highlighting]
+
+.zimrc Configuration
+--------------------
+
+  * `zhighlighters=(main brackets cursor)` add any highlighters you want as described [here](https://github.com/zsh-users/zsh-syntax-highlighting/blob/master/docs/highlighters.md#zsh-syntax-highlighting--highlighters).
+
+Contributing
+------------
+
+Contributions should be submitted [upstream to zsh-syntax-highlighting](https://github.com/zsh-users/zsh-syntax-highlighting)
+
+[syntax_highlighting]: http://i.eriner.me/zim_syntax-highlighting.gif