updated short description of indexOfOp

Author: markusvoelter

code/languages/org.iets3.opensource/languages/org.iets3.core.expr.collections/models/structure.mps

@@ -1214,7 +1214,7 @@
     <property role="TrG5h" value="IndexOfOp" />
     <property role="34LRSv" value="indexOf" />
     <property role="EcuMT" value="1406572792884327605" />
-    <property role="R4oN_" value="returns first N elements" />
+    <property role="R4oN_" value="find the position of the argument in the list" />
     <ref role="1TJDcQ" node="6zmBjqUjnKs" resolve="OneArgCollectionOp" />
     <node concept="PrWs8" id="1e59C2QAniR" role="PzmwI">
       <ref role="PrY4T" node="6zmBjqUiHHJ" resolve="IOrderedCollectionOp" />