fix issue #983

Do not adjust userCompletionText while finding userCompletion text position
when match contains `{` in CompletionText[1], and preserve the splat sigil
at start of completions of type `Variable`.

Adjusting userCompletionText led to selection box consuming sigil for
braced variables, or crash on incorrectly braced splats.

Author: msftrncs

PSReadLine/Completion.cs

@@ -1,4 +1,4 @@
-/********************************************************************++
+/********************************************************************++
 Copyright (c) Microsoft Corporation.  All rights reserved.
 --********************************************************************/
 
@@ -106,7 +106,7 @@ private static string GetUnquotedText(CompletionResult match, bool consistentQuo
             {
                 if (IsQuotedVariable(s))
                 {
-                    return '$' + s.Substring(2, s.Length - 3);
+                    return s[0] + s.Substring(2, s.Length - 3);
                 }
                 return s;
             }
@@ -731,9 +731,7 @@ private Collection<CompletionResult> FilterCompletions(CommandCompletion complet
 
         private int FindUserCompletionTextPosition(CompletionResult match, string userCompletionText)
         {
-            return match.ResultType == CompletionResultType.Variable && match.CompletionText[1] == '{'
-                ? match.CompletionText.IndexOf(userCompletionText.Substring(1), StringComparison.OrdinalIgnoreCase) - 1
-                : match.CompletionText.IndexOf(userCompletionText, StringComparison.OrdinalIgnoreCase);
+            return match.CompletionText.IndexOf(userCompletionText, StringComparison.OrdinalIgnoreCase);
         }
 
         private bool IsDoneWithCompletions(CompletionResult currentCompletion, PSKeyInfo nextKey)