fix: Update src/NetEvolve.CodeBuilder/CSharpCodeBuilder.Append.cs

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>
Signed-off-by: Martin Stühmer <me@samtrion.net>

Author: samtrion

src/NetEvolve.CodeBuilder/CSharpCodeBuilder.Append.cs

@@ -206,19 +206,21 @@ public CSharpCodeBuilder Append(ReadOnlySpan<char> value)
     /// <remarks>If the span is empty, the method returns without appending anything.</remarks>
     public CSharpCodeBuilder Append(ReadOnlySpan<char> value, int startIndex, int count)
     {
-        if (value.IsEmpty)
+        var slice = value.Slice(startIndex, count);
+        if (slice.IsEmpty)
         {
             return this;
         }
 
         EnsureIndented();
-#if NETSTANDARD2_0
-        _ = _builder.Append(value.Slice(startIndex, count).ToString());
-#else
-        _ = _builder.Append(value.Slice(startIndex, count));
-#endif
+`#if` NETSTANDARD2_0
+        _ = _builder.Append(slice.ToString());
+`#else`
+        _ = _builder.Append(slice);
+`#endif`
         return this;
     }
+    }
 
     /// <summary>
     /// Appends a subset of a string to the current builder.