Fix - Make sure position is never negative.

Author: Maxime Labelle

PSReadLine/ViRegister.cs

@@ -168,7 +168,7 @@ public int PasteBefore(StringBuilder buffer, int position)
 
                     // we adjust the current position to prevent a crash
 
-                    position = Math.Min(position, buffer.Length - 1);
+                    position = Math.Max(0, Math.Min(position, buffer.Length - 1));
 
                     var text = _text;