Add documentation on IT_INSERT operator

README.md

@@ -544,6 +544,7 @@ Other documented operators are:
 * IT\_PREVIOUS(it\_obj): Move the iterator to the previous sub-component. The direction of PREVIOUS is container dependent, but it is assumed to be the reverse of NEXT.
 * IT\_CREF(it\_obj) --> &obj: Return a constant pointer to the object referenced by the iterator. This pointer is valid until any modifying operation on the container, or until another reference is taken from this container (some particular container may reduce theses constraints).
 * IT\_REF(it\_obj) --> &obj: Return a pointer to the object referenced by the iterator. This pointer is valid until any modifying operation on the container, or until another reference is taken from this container (some particular container may reduce theses constraints).
+* IT\_INSERT(container, it\_obj, obj): Insert 'obj' after 'it\_obj' in the container and update it\_obj to point to the inserted object. All other iterators of the same container become invalidated.
 * IT\_REMOVE(container, it\_obj): Remove it\_obj from the container (clearing the associated object) and update it\_obj to point to the next object. All other iterators of the same container become invalidated.
 * OUT\_STR(FILE* f, obj): Output 'obj' as a string into the FILE stream 'f'.
 * IN\_STR(obj, FILE* f) --> bool: Set 'obj' to the value associated to the string representation of the object in the FILE stream 'f'. Return true in case of success (in that case the stream 'f' has been advanced to the end of the parsing of the object), false otherwise (in that case, the stream 'f' is in an undetermined position but is likely where the parsing fails).