Make sure all packages include the note about SponsorLink

This should account for nuget.org's Code of Conduct #5:

> 5. Don't engage in activity that is false or misleading
> (e.g., asking for money under false pretenses; impersonating
> someone else; manipulating the Services to increase download
> or install count, or affect rankings, ratings, or comments;
> **or causing unexpected behavior that is not clearly documented
> at the top of both the package description and package README**).

readme.md

@@ -6,8 +6,9 @@
 [![License](https://img.shields.io/github/license/devlooped/ThisAssembly.svg?color=blue)](https://github.com//devlooped/ThisAssembly/blob/main/license.txt)
 [![Build](https://github.com/devlooped/ThisAssembly/workflows/build/badge.svg?branch=main)](https://github.com/devlooped/ThisAssembly/actions)
 
+<!-- include https://github.com/devlooped/.github/raw/main/sponsorlink.md -->
 <!-- #meta -->
-Exposes project and assembly level information as constants in the ThisAssembly 
+Expose project and assembly level information as constants in the ThisAssembly 
 class using source generators powered by Roslyn.
 
 The main generated entry point type is `ThisAssembly` in the global namespace, 

src/ThisAssembly.AssemblyInfo/readme.md

@@ -1,3 +1,4 @@
+<!-- include https://github.com/devlooped/.github/raw/main/sponsorlink.md -->
 <!-- #assembly -->
 This package generates a static `ThisAssembly.Info` class with public 
 constants exposing the following attribute values generated by default for SDK style projects:

src/ThisAssembly.Constants/readme.md

@@ -1,3 +1,4 @@
+<!-- include https://github.com/devlooped/.github/raw/main/sponsorlink.md -->
 <!-- #constants -->
 This package generates a static `ThisAssembly.Constants` class with public
 constants for `@(Constant)` MSBuild items in the project.

src/ThisAssembly.Git/readme.md

@@ -1,3 +1,4 @@
+<!-- include https://github.com/devlooped/.github/raw/main/sponsorlink.md -->
 <!-- #git -->
 This package generates a static `ThisAssembly.Git` class with constants 
 for the following Git properties from the current project:

src/ThisAssembly.Metadata/readme.md

@@ -1,3 +1,4 @@
+<!-- include https://github.com/devlooped/.github/raw/main/sponsorlink.md -->
 <!-- #metadata -->
 This package provides a static `ThisAssembly.Metadata` class with public 
 constants exposing each `[System.Reflection.AssemblyMetadata(..)]` defined for 

src/ThisAssembly.Project/readme.md

@@ -1,3 +1,4 @@
+<!-- include https://github.com/devlooped/.github/raw/main/sponsorlink.md -->
 <!-- #project -->
 This package generates a static `ThisAssembly.Project` class with public 
 constants exposing project properties that have been opted into this mechanism by adding 

src/ThisAssembly.Resources/readme.md

@@ -1,3 +1,4 @@
+<!-- include https://github.com/devlooped/.github/raw/main/sponsorlink.md -->
 <!-- #resources -->
 
 This package generates a static `ThisAssembly.Resources` class with public 

src/ThisAssembly.Strings/readme.md

@@ -1,3 +1,4 @@
+<!-- include https://github.com/devlooped/.github/raw/main/sponsorlink.md -->
 <!-- #strings -->
 
 This package generates a static `ThisAssembly.Strings` class with public 

src/ThisAssembly/readme.md

@@ -1,3 +1,4 @@
+<!-- include https://github.com/devlooped/.github/raw/main/sponsorlink.md -->
 <!-- include ../../readme.md#meta -->
 
 ## ThisAssembly.AssemblyInfo