Fix link to keyword and numeric type

docs/reference/search/request/collapse.asciidoc

@@ -30,7 +30,7 @@ GET /twitter/tweet/_search
 WARNING: The total number of hits in the response indicates the number of matching documents without collapsing.
 The total number of distinct group is unknown.
 
-The field used for collapsing must be a single valued <<keyword, `keyword`> or <<number, `number`>> field with <<doc-values, `doc_values`>> activated
+The field used for collapsing must be a single valued <<keyword, `keyword`>> or <<number, `numeric`>> field with <<doc-values, `doc_values`>> activated
 
 NOTE: The collapsing is applied to the top hits only and does not affect aggregations.