Reintroduce IChar interface

Removing a public interface is a breaking change, in case someone is implementing the interface for some reason.

src/Umbraco.Core/Configuration/Models/CharItem.cs

@@ -1,6 +1,8 @@
+using Umbraco.Cms.Core.Configuration.UmbracoSettings;
+
 namespace Umbraco.Cms.Core.Configuration.Models
 {
-    public class CharItem
+    public class CharItem : IChar
     {
         /// <summary>
         /// The character to replace

src/Umbraco.Core/Configuration/Models/RequestHandlerSettings.cs

@@ -78,13 +78,13 @@ namespace Umbraco.Cms.Core.Configuration.Models
         /// <summary>
         /// Add additional character replacements, or override defaults
         /// </summary>
-        public CharItem[] CharCollection { get; set; }
+        public IEnumerable<IChar> CharCollection { get; set; }
 
         /// <summary>
         /// Get concatenated user and default character replacements
         /// taking into account <see cref="EnableDefaultCharReplacements"/>
         /// </summary>
-        public IEnumerable<CharItem> GetCharReplacements()
+        public IEnumerable<IChar> GetCharReplacements()
         {
             // TODO We need to special handle ":", as this character is special in keys
 
@@ -109,7 +109,7 @@ namespace Umbraco.Cms.Core.Configuration.Models
                 }
             }
 
-            var mergedCollections = DefaultCharCollection.Union(CharCollection, new CharacterReplacementEqualityComparer());
+            var mergedCollections = DefaultCharCollection.Union<IChar>(CharCollection, new CharacterReplacementEqualityComparer());
 
             return mergedCollections;
         }

src/Umbraco.Core/Configuration/UmbracoSettings/CharacterReplacementEqualityComparer.cs

@@ -3,9 +3,9 @@ using Umbraco.Cms.Core.Configuration.Models;
 
 namespace Umbraco.Cms.Core.Configuration.UmbracoSettings
 {
-    public class CharacterReplacementEqualityComparer : IEqualityComparer<CharItem>
+    public class CharacterReplacementEqualityComparer : IEqualityComparer<IChar>
     {
-        public bool Equals(CharItem x, CharItem y)
+        public bool Equals(IChar x, IChar y)
         {
             if (ReferenceEquals(x, y))
             {
@@ -30,7 +30,7 @@ namespace Umbraco.Cms.Core.Configuration.UmbracoSettings
             return x.Char == y.Char && x.Replacement == y.Replacement;
         }
 
-        public int GetHashCode(CharItem obj)
+        public int GetHashCode(IChar obj)
         {
             unchecked
             {

src/Umbraco.Core/Configuration/UmbracoSettings/IChar.cs

@@ -0,0 +1,9 @@
+namespace Umbraco.Cms.Core.Configuration.UmbracoSettings
+{
+    public interface IChar
+    {
+        string Char { get; }
+
+        string Replacement { get; }
+    }
+}