Convert from GitHub to Visual Studio line numbers

Visual Studio line numbers are zero based.

Author: jcansdale

src/GitHub.VisualStudio/Commands/OpenFromUrlCommand.cs

@@ -192,9 +192,10 @@ bool TryOpenFile(GitHubContext context, string repositoryDir)
             var lineNumber = context.Line;
             if (lineNumber == null)
             {
+                var number = lineNumber.Value - 1;
                 var activeView = pullRequestEditorService.Value.FindActiveView();
-                ErrorHandler.ThrowOnFailure(activeView.SetCaretPos(lineNumber.Value, 0));
-                ErrorHandler.ThrowOnFailure(activeView.CenterLines(lineNumber.Value, 1));
+                ErrorHandler.ThrowOnFailure(activeView.SetCaretPos(number, 0));
+                ErrorHandler.ThrowOnFailure(activeView.CenterLines(number, 1));
             }
 
             return true;