Re-enable Codementor site detection and update documentation

Author: Kavindya-Kariyawasam

docs/removed-sites.md

@@ -176,21 +176,6 @@ As of 2019-12-31, all usernames are reported as existing.
   },
 ```
 
-## Codementor
-
-As of 2019-12-31, usernames that exist are not detected.
-
-```json
-  "Codementor": {
-    "errorType": "status_code",
-    "rank": 10252,
-    "url": "https://www.codementor.io/@{}",
-    "urlMain": "https://www.codementor.io/",
-    "username_claimed": "blue",
-    "username_unclaimed": "noonewouldeverusethis7"
-  },
-```
-
 ## KiwiFarms
 
 As of 2019-12-31, the site gives a 403 for all usernames.  You have to

sherlock_project/resources/data.json

@@ -485,6 +485,12 @@
     "urlProbe": "https://codeforces.com/api/user.info?handles={}",
     "username_claimed": "tourist"
   },
+  "Codementor": {
+    "errorType": "status_code",
+    "url": "https://www.codementor.io/@{}",
+    "urlMain": "https://www.codementor.io/",
+    "username_claimed": "blue"
+  },
   "Codepen": {
     "errorType": "status_code",
     "url": "https://codepen.io/{}",