Nullable.Value → Nullable.GetValueOrDefault (#17504)

* We are already checking `Nullable.HasValue` before accessing
  `Nullable.Value`, so it is safe to call `Nullable.GetValueOrDefault`,
  which does not do an additional check, unlike `Nullable.Value`.

Author: brianrourkeboll

src/FSharp.Core/option.fs

@@ -148,7 +148,7 @@ module Option =
     [<CompiledName("OfNullable")>]
     let inline ofNullable (value: System.Nullable<'T>) =
         if value.HasValue then
-            Some value.Value
+            Some (value.GetValueOrDefault())
         else
             None
 
@@ -338,7 +338,7 @@ module ValueOption =
     [<CompiledName("OfNullable")>]
     let inline ofNullable (value: System.Nullable<'T>) =
         if value.HasValue then
-            ValueSome value.Value
+            ValueSome (value.GetValueOrDefault())
         else
             ValueNone