Minor whitespace cleanup and removal of unused Slack reference

docs/contributing/contributing.md

@@ -1,11 +1,10 @@
 | [docs](..)  / [contributing](.) / contributing.md
 |:---|
 
-# Contributing
-
+# Contributing
+
 Why not give back and help make Squirrel even better? Here is an overview of ways you can become more involved.
 
-* **Join the Squirrel Slack Room** - email [[email protected]](mailto:[email protected]) with the email address you'd like to receive an invite.
 * **Contribute Documentation** - improve the documentation or provide additional code examples to benefit others.
 * **Subscribe to Issues on GitHub** - have some experience using Squirrel? Help answer questions under issues or post a Pull Request fixing a bug.
 * **Contribute Code** -  have a great feature that you feel is a good fit for Squirrel? Send a Pull Request.

docs/readme.md

@@ -47,8 +47,8 @@ The **[Getting Started Guide](getting-started/0-overview.md)** provides a step-b
   * [GitHub](using/github.md) - overview of using GitHub for installing, distributing, and updating.
 * **Updating** - documentation related to updating an existing install via the `UpdateManager`.
   * [Update Process](using/update-process.md) - overview of the steps in the update process.
-  * [Update Manager](using/update-manager.md) - reference guide for the `UpdateManager`.  
-  * [GitHub](using/github.md) - overview of using GitHub for installing, distributing, and updating.  
+  * [Update Manager](using/update-manager.md) - reference guide for the `UpdateManager`.
+  * [GitHub](using/github.md) - overview of using GitHub for installing, distributing, and updating.
   * [Debugging Updates](using/debugging-updates.md) - tips for debugging Squirrel.Windows updates.
   * [Staged Rollouts](using/staged-rollouts.md) - how to use staged rollouts to ramp up install distribution over time