Fix typo in the docs (#864)

* Make externally provided errors work with paper-autocomplete

Pass isTouched from paper-autocomplete to paper-autocomplete-trigger
and its inner paper-input.

* Fix typo in the docs

tests/dummy/app/templates/theme.hbs

@@ -6,7 +6,7 @@
   <p>
     <code>ember-paper</code> uses the same color palettes and palette names as
     Angular Material and <a href="https://material.google.com/style/color.html">Material Design</a>.
-    Each pallete contains 14 shades/tints of the specified hue for use by components
+    Each palette contains 14 shades/tints of the specified hue for use by components
     in diffierent situations. The definitive shade/tint is <code>'500'</code>.
     Specify the desired palette(s) prior to importing <code>ember-paper.scss</code>.
   </p>