Adds support for C-d delete

Fixes tonerdo#40

Author: rubberduck203

README.md

@@ -29,7 +29,7 @@ It is cross platform and runs anywhere .NET is supported, targeting `netstandard
 | `Ctrl`+`U`                     | Cut text to the start of line     |
 | `Ctrl`+`W`                     | Cut previous word                 |
 | `Backspace`                    | Delete previous character         |
-| `Delete`                       | Delete succeeding character       |
+| `Ctrl` + `D` / `Delete`        | Delete succeeding character       |
 
 
 ## Installation

src/ReadLine/KeyHandler.cs

@@ -238,6 +238,7 @@ public KeyHandler(IConsole console, List<string> history, IAutoCompleteHandler a
             _keyActions["ControlE"] = MoveCursorEnd;
             _keyActions["Backspace"] = Backspace;
             _keyActions["Delete"] = Delete;
+            _keyActions["ControlD"] = Delete;
             _keyActions["ControlH"] = Backspace;
             _keyActions["ControlL"] = ClearLine;
             _keyActions["Escape"] = ClearLine;

test/ReadLine.Tests/KeyHandlerTests.cs

@@ -201,6 +201,21 @@ public void TestRightArrow()
             Assert.Equal("Hello!", _keyHandler.Text);
         }
 
+        [Fact]
+        public void TestControlD()
+        {
+            for (var i = 0; i < 4; i++)
+            {
+                _keyInfo = new ConsoleKeyInfo('\0', ConsoleKey.LeftArrow, false, false, false);
+                _keyHandler.Handle(_keyInfo);
+            }
+
+            _keyInfo = new ConsoleKeyInfo('\u0004', ConsoleKey.D, false, false, true);
+            _keyHandler.Handle(_keyInfo);
+
+            Assert.Equal("Hllo", _keyHandler.Text);
+        }
+
         [Fact]
         public void TestControlF()
         {