[sledge] Doc: Update doc of Term.map_rec_pre

Summary: Remove mention of cyclic terms, they no exist.

Reviewed By: jvillard

Differential Revision: D21721004

fbshipit-source-id: f57ebdc2a

sledge/src/term.mli

@@ -243,12 +243,11 @@ val rec_record : int -> t
 val map : t -> f:(t -> t) -> t
 
 val map_rec_pre : t -> f:(t -> t option) -> t
-(** Pre-order transformation that preserves cycles. Each subterm [x] from
+(** Pre-order transformation. Each subterm [x] from root to leaves is
-    root to leaves is presented to [f]. If [f x = Some x'] then the subterms
+    presented to [f]. If [f x = Some x'] then the subterms of [x] are not
-    of [x] are not traversed and [x] is transformed to [x']. Otherwise
+    traversed and [x] is transformed to [x']. Otherwise traversal proceeds
-    traversal proceeds to the subterms of [x], followed by rebuilding the
+    to the subterms of [x], followed by rebuilding the term structure on the
-    term structure on the transformed subterms. Cycles (through terms
+    transformed subterms. *)
-    involving [RecN]) are preserved. *)
 
 val fold_map : t -> init:'a -> f:('a -> t -> 'a * t) -> 'a * t