added method in StringOperations.cs

Author: oni-shiro

src/TestableIO.System.IO.Abstractions.TestingHelpers/StringOperations.cs

@@ -37,6 +37,10 @@ public StringOperations(bool caseSensitive)
     /// </summary>
     public bool Equals(string x, string y) => string.Equals(x, y, comparison);
     /// <summary>
+    /// Determines whether the given strings are equal using the given comparison type.
+    /// </summary>
+    public bool Equals(string x, string y, StringComparison comparison) => string.Equals(x, y, comparison);
+    /// <summary>
     /// Determines whether the given characters are equal.
     /// </summary>
     public bool Equals(char x, char y) => caseSensitive ? x == y : char.ToUpper(x) == char.ToUpper(y);