Field does not show up in list of fields

Problem/Motivation

After installing the module (version 2.0.4) and clearing the cache, the field does not appear in the list of fields when adding a new field.

Steps to reproduce

1. Install Module
2. Clear Cache
3. Add a field to a content type
4. "Display Mode" is not an option

Proposed resolution

The issue is in the field definition of the field type file. The category says "reference" when it should have a capital R.

Current:

/**
 * Plugin implementation of the 'entity_reference_display' field type. 
 *
 * @FieldType(
 *   id = "entity_reference_display",
 *   label = @Translation("Display mode"),
 *   description = @Translation("This field allows you to specify a display mode for entity reference field."),
 *   category = "reference",
 *   default_widget = "options_select",
 *   default_formatter = "list_default"
 * )
 */

Fix:

/**
 * Plugin implementation of the 'entity_reference_display' field type.
 *
 * @FieldType(
 *   id = "entity_reference_display",
 *   label = @Translation("Display mode"),
 *   description = @Translation("This field allows you to specify a display mode for entity reference field."),
 *   category = @Translation("Reference"),
 *   default_widget = "options_select",
 *   default_formatter = "list_default"
 * )
 */