Settings: edit dictionary, disable spellcheck

Bug: 866359
Change-Id: I5bae80bafd34446eaa35b74d79cb35acb5ba5b6c
Reviewed-on: https://chromium-review.googlesource.com/1146991Reviewed-by: Scott Chen <scottchen@chromium.org>
Commit-Queue: Esmael El-Moslimany <aee@chromium.org>
Cr-Commit-Position: refs/heads/master@{#577257}

chrome/browser/resources/settings/languages_page/edit_dictionary_page.html

@@ -37,7 +37,8 @@
           invalid="[[isWordInvalid_(newWordValue_)]]"
           error-message="[[isWordInvalid_(newWordValue_,
               '$i18nPolymer{addDictionaryWordDuplicateError}',
-              '$i18nPolymer{addDictionaryWordLengthError}')]]">
+              '$i18nPolymer{addDictionaryWordLengthError}')]]"
+          spellcheck="false">
         <paper-button class="secondary-button" on-click="onAddWordTap_"
             disabled="[[disableAddButton_(newWordValue_)]]" id="addWord"
             slot="suffix">