Add Datamuse (#1756)

README.md

@@ -759,6 +759,7 @@ API | Description | Auth | HTTPS | CORS |
 |---|---|---|---|---|
 | [Countly](https://api.count.ly/reference) | Countly web analytics | No | No | Unknown |
 | [Creative Commons Catalog](https://api.creativecommons.engineering/) | Search among openly licensed and public domain works | `OAuth` | Yes | Yes |
+| [Datamuse](https://www.datamuse.com/api/) | Word-finding query engine | No | Yes | Unknown |
 | [Drupal.org](https://www.drupal.org/drupalorg/docs/api) | Drupal.org | No | Yes | Unknown |
 | [Evil Insult Generator](https://evilinsult.com/api) | Evil Insults | No | Yes | Yes |