Add day 2

StringExtensions.cs

@@ -0,0 +1,17 @@
+namespace AdventOfCode;
+
+public static class StringExtensions
+{
+    public static IEnumerable<string> ReadAllLines(this StringReader reader)
+    {
+        while (reader.ReadLine() is { } line)
+        {
+            yield return line;
+        }
+    }
+
+    public static IEnumerable<string> ReadAllLines(this string text)
+    {
+        return new StringReader(text).ReadAllLines();
+    }
+}