test: Fix assertion to reveal issue

Author: HulinCedric

solution/c#/Day14/Day14.Tests/LangExt/FizzBuzzTests.cs

@@ -1,3 +1,4 @@
+using FluentAssertions;
 using FluentAssertions.LanguageExt;
 using Xunit;
 
@@ -22,7 +23,10 @@ public void Returns_Number_Representation(int input, string expectedResult)
             => Day14.LangExt.FizzBuzz
                 .Convert(input)
                 .Should()
-                .BeSome(expectedResult);
+                .BeSome()
+                .Which
+                .Should()
+                .Be(expectedResult);
 
         [Theory]
         [InlineData(0)]