normalize autocomplete and spellcheck

src/components/input/input.vue

@@ -9,6 +9,7 @@
             <input
                 :id="elementId"
                 :autocomplete="autocomplete"
+                :spellcheck="spellcheck"
                 ref="input"
                 :type="type"
                 :class="inputClasses"
@@ -34,6 +35,7 @@
             v-else
             :id="elementId"
             :autocomplete="autocomplete"
+            :spellcheck="spellcheck"
             ref="textarea"
             :class="textareaClasses"
             :style="textareaStyles"
@@ -116,6 +118,10 @@
                 type: Boolean,
                 default: false
             },
+            spellcheck: {
+                type: Boolean,
+                default: false
+            },
             autocomplete: {
                 validator (value) {
                     return oneOf(value, ['on', 'off']);