doc/ck_epoch: update poll and synchronize clarifying expected record state.

doc/ck_epoch_poll

@@ -47,10 +47,9 @@ if deemed safe. This function is meant to be used in cases epoch
 reclamation cost must be amortized over time in a manner that does
 not affect caller progress.
 .Sh RETURN VALUES
-This function will return true if at least one function was dispatched.
+This functions returns false if no memory was reclaimed, the records
-This function will return false if it has determined not all threads have
+are not in a grace period or if no forward progress was made to the
-observed the latest generation of epoch-protected objects. Neither value
+counter.
-indicates an error.
 .Sh ERRORS
 Behavior is undefined if the object pointed to by
 .Fa record

doc/ck_epoch_synchronize

@@ -40,6 +40,8 @@ The
 .Fn ck_epoch_synchronize 3
 function will block the caller until a grace period has been
 detected, according to the semantics of epoch reclamation.
+It is not safe to call this function on a record that is
+in an active section.
 Any objects requiring safe memory reclamation which are logically
 deleted are safe for physical deletion following a call to
 .Fn ck_epoch_synchronize 3 .