Fix edge-case issues with Help functionality; modernize features

SabreTools.Help/Int32Feature.cs

@@ -0,0 +1,68 @@
+using System;
+using System.Text;
+
+namespace SabreTools.Help
+{
+    public class Int32Feature : Feature<int>
+    {
+        #region Constructors
+
+        public Int32Feature(string name, string flag, string description, string? longDescription = null)
+            : base(name, flag, description, longDescription)
+        {
+        }
+
+        public Int32Feature(string name, string[] flags, string description, string? longDescription = null)
+            : base(name, flags, description, longDescription)
+        {
+        }
+
+        #endregion
+
+        #region Instance Methods
+
+        /// <inheritdoc/>
+        public override bool ValidateInput(string input, bool exact = false, bool ignore = false)
+        {
+            // Pre-split the input for efficiency
+            string[] splitInput = input.Split('=');
+
+            bool valid = input.Contains("=") && Flags.Contains(splitInput[0]);
+            if (valid)
+            {
+                if (!int.TryParse(splitInput[1], out int value))
+                    value = int.MinValue;
+
+                Value = value;
+
+                // If we've already found this feature before
+                if (_foundOnce && !ignore)
+                    valid = false;
+
+                _foundOnce = true;
+            }
+
+            // If we haven't found a valid flag and we're not looking for just this feature, check to see if any of the subfeatures are valid
+            if (!valid && !exact)
+            {
+                string[] featureKeys = [.. Features.Keys];
+                valid = Array.Exists(featureKeys, k => Features[k]!.ValidateInput(input));
+            }
+
+            return valid;
+        }
+
+        /// <inheritdoc/>
+        public override bool IsEnabled() => Value != int.MinValue;
+
+        /// <inheritdoc/>
+        protected override string FormatFlags()
+        {
+            var sb = new StringBuilder();
+            Flags.ForEach(flag => sb.Append($"{flag}=, "));
+            return sb.ToString().TrimEnd(' ', ',');
+        }
+
+        #endregion
+    }
+}