bugfix to flatten-clases simplifier

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

src/tactic/arith/add_bounds_tactic.h

@@ -7,13 +7,33 @@ Module Name:
 
 Abstract:
 
-    Tactic for bounding unbounded variables.
+    
 
 Author:
 
     Leonardo de Moura (leonardo) 2011-06-30.
 
-Revision History:
+Tactic Documentation:
+
+## Tactic add-bounds
+
+### Short Description
+
+Tactic for bounding unbounded variables.
+
+### Long Description
+
+The tactic creates a stronger sub-goal by adding bounds to variables.
+The new goal may not be satisfiable even if the original goal is.
+
+### Example
+
+```z3
+(declare-const x Int)
+(declare-const y Int)
+(assert (> (+ x y) 10))
+(apply add-bounds)
+```
 
 --*/
 #pragma once