Remove warning "overwriting-delimiting-key"

The delimiter is in fact not overwritten for parsing (ie both the old
and new delimiters are accepted), it is only replaced for printing.
IMO this means it's not worth warning about.

interp/notation.ml

@@ -224,9 +224,6 @@ let warn_scope_delimiter_start_ =
     ~default:CWarnings.AsError
     (fun () -> strbrk "Scope delimiters should not start with an underscore.")
 
-let warn_overwriting_key = CWarnings.create ~name:"overwriting-delimiting-key" ~category:CWarnings.CoreCategories.parsing
-    Pp.(fun (oldkey,scope) -> str "Overwriting previous delimiting key " ++ str oldkey ++ str " in scope " ++ str scope)
-
 let warn_hiding_key =  CWarnings.create ~name:"hiding-delimiting-key" ~category:CWarnings.CoreCategories.parsing
     Pp.(fun (key,oldscope) -> str "Hiding binding of key " ++ str key ++ str " to " ++ str oldscope)
 
@@ -237,10 +234,7 @@ let declare_delimiters scope key =
   begin match sc.delimiters with
     | None -> scope_map := String.Map.add scope newsc !scope_map
     | Some oldkey when String.equal oldkey key -> ()
-    | Some oldkey ->
-      (* FIXME: implement multikey scopes? *)
-      warn_overwriting_key (oldkey,scope);
-      scope_map := String.Map.add scope newsc !scope_map
+    | Some oldkey -> scope_map := String.Map.add scope newsc !scope_map
   end;
   try
     let oldscope = String.Map.find key !delimiters_map in

test-suite/output/DelimitScope.out

@@ -0,0 +1,8 @@
+(~~ false)%bool
+     : bool
+(~~ false)%B
+     : bool
+(~~ false)%B
+     : bool
+(~~ false)%B
+     : bool

test-suite/output/DelimitScope.v

@@ -0,0 +1,13 @@
+Reserved Notation "~~ b" (at level 35, right associativity).
+
+Notation "~~ b" := (negb b) : bool_scope.
+
+Check negb false.
+
+Delimit Scope bool_scope with B.
+
+Check negb false.
+
+(* %bool still works even if not used by printing *)
+Check (~~ false)%bool.
+Check (~~ false)%B.

theories/ssr/ssrbool.v

@@ -465,9 +465,7 @@ Reserved Notation "[ ==> b1 , b2 , .. , bn => c ]" (at level 0, format
   "'[hv' [ ==> '['  b1 , '/'  b2 , '/'  .. , '/'  bn ']' '/'  =>  c ] ']'").
 
 (**  Shorter delimiter  **)
-#[export] Set Warnings "-overwriting-delimiting-key".
 Delimit Scope bool_scope with B.
-#[export] Set Warnings "overwriting-delimiting-key".
 Open Scope bool_scope.
 
 (**  An alternative to xorb that behaves somewhat better wrt simplification. **)