message: Hide autocomplete on Enter key press instead of sending message
diff: @@ -1046,6 +1046,12 @@ export default class MessageComposerInput extends React.Component {
  return change.insertText('\n');
  }
  + if (this.autocomplete.countCompletions() > 0) {
  + this.autocomplete.hide();
  + ev.preventDefault();
  + return true;
  + }
  +
  const editorState = this.state.editorState;
  const lastBlock = editorState.blocks.last();
  