Update doc

Author: kayceesrk

src/lf_msqueue.mli

@@ -17,15 +17,35 @@
 
 module type S = sig
   type 'a t
+  (** The type of lock-free queue. *)
+
   val create      : unit -> 'a t
+  (** Create a new queue, which is initially empty. *)
+
   val is_empty    : 'a t -> bool
+  (** [is_empty q] returns empty if [q] is empty. *)
+
   val push        : 'a t -> 'a -> unit
+  (** [push q v] pushes [v] to the back of the queue. *)
+
   val pop         : 'a t -> 'a option
+  (** [pop q] pops an element [e] from the front of the queue and returns 
+      [Some v] if the queue is non-empty. Otherwise, returns [None]. *)
+
   val clean_until : 'a t -> ('a -> bool) -> unit
+  (** [clean_until q f] drops the prefix of the queue until the element [e],
+      where [f e] is [true]. If no such element exists, then the queue is
+      emptied. *)
 
   type 'a cursor
+  (** The type of cursor. *)
+
   val snapshot  : 'a t -> 'a cursor
+  (** Obtain a snapshot of the queue. This is a constant time operation. *)
+
   val next      : 'a cursor -> ('a * 'a cursor) option
+  (** [next c] returns [Some (e, c')] where [e] is the head of the queue and
+      [c'] is the tail, if the queue is non-empty. Otherwise, returns [None]. *)
 end
 
 module M : S