fix typo in boolean error

Author: michaelgmcd

jscomp/common/bs_warnings.ml

@@ -39,7 +39,7 @@ let to_string t =
  match t with
  | Unsafe_ffi_bool_type
  -> 
- "You are passing a OCaml bool type into JS, probabaly you want to pass Js.boolean"
+ "You are passing a OCaml bool type into JS, probably you want to pass Js.boolean"
  | Unsafe_poly_variant_type 
  -> 
  "Here a OCaml polymorphic variant type passed into JS, probably you forgot annotations like `[@bs.int]` or `[@bs.string]` "