Rearrange the wording for OSes (#899)

* Rearrange the wording for OSes

* Update capitalization

* Add a space in between

main/guides/getting-started/README.md

@@ -13,7 +13,7 @@ Before getting started, there are some resources you might want to keep handy in
 
 
 ## Platform Requirements
-Currently Agoric supports [Windows Subsystem for Linux](https://learn.microsoft.com/en-us/windows/wsl/about), MacOS, and Linux. This tutorial is based on an installation of [Ubuntu 22.04 LTS](https://ubuntu.com/download/desktop). If you're using a different operating system, some variation may be required.
+Currently Agoric supports macOS and Linux (including [Windows Subsystem for Linux](https://learn.microsoft.com/en-us/windows/wsl/about)). This tutorial is based on an installation of [Ubuntu 22.04 LTS](https://ubuntu.com/download/desktop). If you're using a different operating system, some variation may be required.
 
 ## Installing Prerequisites
 In this section you'll be installing prerequisite components into your environment. If you're working with your own environment rather than using a fresh Ubuntu install, you may already have some or all of these components already installed.
@@ -182,7 +182,7 @@ yarn install
  If you run into errors during `yarn install`, check that you are on a [supported platform](#platform-requirements) and not native Windows. 
 
  Then make sure you have the relevant developer tools installed. For example, on Debian or Ubuntu Linux, run `sudo apt get install build-essential`. 
- On MacOS, be sure to install [Xcode](https://apps.apple.com/us/app/xcode/id497799835). 
+ On macOS, be sure to install [Xcode](https://apps.apple.com/us/app/xcode/id497799835). 
 
   </details>