Added note on Python3 and MacOS

docs/language_servers.md

@@ -21,9 +21,12 @@ chmod 755 /usr/local/bin/javascript-language-server
 
 ## Python3
 * Prerequisites:
-    * Python3
     * In juCi++ preferences, set `project.python_command` to `PYTHONUNBUFFERED=1 python3`
-  
+    * Python3
+        * MacOS: Jedi does not yet support Python 3.6, but you can install latest 3.5 version:
+            
+            `brew install https://raw.githubusercontent.com/Homebrew/homebrew-core/f2a764ef944b1080be64bd88dca9a1d80130c558/Formula/python.rb`
+
 Install language server, and create symbolic link to enable server in juCi++:
 ```sh
 pip3 install python-language-server[rope,pycodestyle,yapf] pyls-mypy