attempt to fix the missing reference

Author: dadhi

CsToMd/source.extension.vsixmanifest

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <PackageManifest Version="2.0.0" xmlns="http://schemas.microsoft.com/developer/vsx-schema/2011" xmlns:d="http://schemas.microsoft.com/developer/vsx-schema-design/2011">
     <Metadata>
-        <Identity Id="CsToMd.13e98d61-1f50-4acd-8e25-099cf4b733f3" Version="1.1.0" Language="en-US" Publisher="dadhi" />
+        <Identity Id="CsToMd.13e98d61-1f50-4acd-8e25-099cf4b733f3" Version="1.1.1" Language="en-US" Publisher="dadhi" />
         <DisplayName>CsToMd</DisplayName>
         <Description xml:space="preserve">Generates a Markdown .md file from the input C# .cs file removing the `/*md` and `md*/` comment lines</Description>
         <MoreInfo>https://github.com/dadhi/Cstomd</MoreInfo>
@@ -11,7 +11,7 @@
         <PreviewImage>screen1.png</PreviewImage>
         <Tags>CSharp;Markdown;md;FileGenerator;TemplateGenerator;LiterateProgramming;Documentation;LiveDocumentation;RunnableSamples</Tags>
     </Metadata>
-    <Installation>
+    <Installation AllUsers="true">
         <InstallationTarget Id="Microsoft.VisualStudio.Pro" Version="[15.0, 17.0)" />
         <InstallationTarget Version="[15.0,17.0)" Id="Microsoft.VisualStudio.Community" />
         <InstallationTarget Version="[15.0,17.0)" Id="Microsoft.VisualStudio.Enterprise" />
@@ -21,7 +21,7 @@
         <Dependency Id="Microsoft.VisualStudio.MPF.15.0" DisplayName="Visual Studio MPF 15.0" d:Source="Installed" Version="[15.0]" />
     </Dependencies>
     <Prerequisites>
-        <Prerequisite Id="Microsoft.VisualStudio.Component.CoreEditor" Version="[15.0,16.0)" DisplayName="Visual Studio core editor" />
+        <Prerequisite Id="Microsoft.VisualStudio.Component.CoreEditor" Version="[16.1.28811.260,17.0)" DisplayName="Visual Studio core editor" />
     </Prerequisites>
     <Assets>
         <Asset Type="Microsoft.VisualStudio.VsPackage" d:Source="Project" d:ProjectName="%CurrentProject%" Path="|%CurrentProject%;PkgdefProjectOutputGroup|" />