Fixed replace logic

Author: linkdotnet

src/LinkDotNet.StringBuilder/ValueStringBuilder.Replace.cs

@@ -141,7 +141,7 @@ public void Replace(scoped ReadOnlySpan<char> oldValue, scoped ReadOnlySpan<char
             if (delta < 0)
             {
                 newValue.CopyTo(buffer[index..]);
-                Remove(index + 1, -delta);
+                Remove(index + newValue.Length, -delta);
             }
 
             // Same length -> We can just replace the memory slice

tests/LinkDotNet.StringBuilder.UnitTests/ValueStringBuilder.Replace.Tests.cs

@@ -57,6 +57,16 @@ public void ShouldReplaceAllText()
         builder.ToString().Should().Be("Hallöchen World. How are you doing. Hallöchen world examples are always fun.");
     }
 
+    [Fact]
+    public void ShouldReplacePart()
+    {
+        using var builder = new ValueStringBuilder("Hello World");
+
+        builder.Replace("Hello", "Ha");
+
+        builder.ToString().Should().Be("Ha World");
+    }
+
     [Theory]
     [InlineData("", "word")]
     [InlineData("word", "")]