Update to emacs 26

See: https://emacs.stackexchange.com/a/43768/12560

lisp/init-org.el

@@ -107,7 +107,7 @@
      (python . t)
      (ruby . t)
      (screen . nil)
-     (sh . t)
+     (shell . t)
      (sql . t)
      (sqlite . t))))