Update service-limits.md

Author: hazemelh

articles/cognitive-services/language-service/conversational-language-understanding/service-limits.md

@@ -95,6 +95,7 @@ The following limits are observed for the conversational language understanding.
 |Count of entities per project | 1 | 500|
 |Count of list synonyms per entity| 0 | 20,000 |
 |Count of prebuilt components per entity| 0 | 7 |
+|Count of regular expressions per project| 0 | 20 |
 |Count of trained models per project| 0 | 10 |
 |Count of deployments per project| 0 | 10 |