Fixes display of per-binding docs in micro-state
Fixes display of per-binding docs in micro-state

Previous behavior, if a micro-state binding had :doc not nil, was an error
  Wrong type argument: stringp, 1

Detailed reproduction:
cat > /tmp/test.el <<EOF
(spacemacs|define-micro-state test
  :doc "[a] a [b] b [q] quit"
  :bindings
  ("a" nil :doc "a")
  ("b" nil :doc "b")
  ("q" nil :doc "quit" :exit t))

(spacemacs/test-micro-state)
EOF
emacs --load /tmp/test.el

Type a, b, or q and see the error in the echo buffer.

tsonntag/dotemacs,tsonntag/dotemacs,tsonntag/dotemacs,tsonntag/dotemacs