[DOCS] Array of index patterns is also valid source indices with transform (#50777)

Author: geekpete

docs/reference/rest-api/common-parms.asciidoc

@@ -772,8 +772,9 @@ end::source-transforms[]
 
 tag::source-index-transforms[]
 The _source indices_ for the {transform}. It can be a single index, an index
-pattern (for example, `"myindex*"`), or an array of indices (for example,
-`["index1", "index2"]`).
+pattern (for example, `"myindex*"`), an array of indices (for example,
+`["index1", "index2"]`), or an array of index patterns (for example,
+`["myindex1-*", "myindex2-*"]`.
 end::source-index-transforms[]
 
 tag::source-query-transforms[]