Ignore case when binding PSReadline keyhandler functions

Fix #4300

src/Microsoft.PowerShell.PSReadLine/Cmdlets.cs

@@ -693,11 +693,18 @@ namespace Microsoft.PowerShell
                 if (ParameterSetName.Equals(FunctionParameterSet))
                 {
                     var function = (string)_dynamicParameters.Value[FunctionParameter].Value;
-                    MethodInfo mi = typeof (PSConsoleReadLine).GetMethod(function);
+                    MethodInfo mi = typeof (PSConsoleReadLine).GetMethod(function,
+                        BindingFlags.Public | BindingFlags.Static | BindingFlags.IgnoreCase);
+
+                    string functionName = mi.Name;
+
                     var keyHandler = (Action<ConsoleKeyInfo?, object>)
                         mi.CreateDelegate(typeof (Action<ConsoleKeyInfo?, object>));
-                    BriefDescription = function;
-                    PSConsoleReadLine.SetKeyHandler(Chord, keyHandler, BriefDescription, Description);
+
+                    string longDescription = PSReadLineResources.ResourceManager.GetString(
+                        functionName + "Description");
+
+                    PSConsoleReadLine.SetKeyHandler(Chord, keyHandler, functionName, longDescription);
                 }
                 else
                 {

src/Microsoft.PowerShell.PSReadLine/ConsoleKeyChordConverter.cs

@@ -79,8 +79,11 @@ namespace Microsoft.PowerShell
                 // key should be first token to be popped
                 if (key == 0)
                 {
-                    // the keyChar is this token
-                    keyChar = token[0];
+                    // the keyChar is this token, if not a special key like "Fxx" etc.
+                    if (token.Length == 1)
+                    {
+                        keyChar = token[0];
+                    }
 
                     // Enum.TryParse accepts arbitrary integers.  We shouldn't,
                     // but single digits need to map to the correct key, e.g.

test/powershell/Modules/PSReadLine/PSReadLine.Tests.ps1

@@ -42,6 +42,12 @@ Describe "PSReadLine" -tags "CI" {
         (Get-PSReadLineKeyHandler | Where-Object { $_.Key -ceq "Alt+B" }).Function | Should Be SelectBackwardWord
     }
 
+    It "Should ignore case when using Function binding" {
+        $lowerCaseFunctionName = "yank"
+        Set-PSReadlineKeyHandler "Ctrl+F24" -Function $lowerCaseFunctionName
+        (Get-PSReadlineKeyHandler | Where { $_.Key -eq "Ctrl+F24"}).Function | Should Be "Yank"
+    }
+
     AfterAll {
         Remove-Module PSReadLine