Update Git setup documentation

Now that everyone needs all the submodules. Much simpler.

README.md

@@ -68,6 +68,32 @@ rules, and Git best practices.
 
 Clone this repository. It is a "superproject" and has a number of
 other repositories embedded within it as submodules. *Please* see the
-contributing guidelines and learn about submodules. Not every
-submodule is required on every system; see the individual build
-instructions for the necessary subsets.
+contributing guidelines and learn about submodules. To make things
+easy, we can just clone recursively.
+
+```sh
+git clone --recursive https://github.com/PowerShell/PowerShell.git
+```
+
+You can verify that the submodules were initialized properly with:
+
+```sh
+git submodule status
+```
+
+If they're initialized, it will look like this:
+
+```
+ f23641488f8d7bf8630ca3496e61562aa3a64009 src/Modules/Pester (f23641488)
+ c99458533a9b4c743ed51537e25989ea55944908 src/libpsl-native/test/googletest (release-1.7.0)
+ e6bf85694ae8352d77175c4c7d304946e018808c src/windows-build (monad/cc6afbeb-3/31)
+```
+
+If they're not, there will be minuses in front (and the folders will
+be empty):
+
+```
+-f23641488f8d7bf8630ca3496e61562aa3a64009 src/Modules/Pester (f23641488)
+-c99458533a9b4c743ed51537e25989ea55944908 src/libpsl-native/test/googletest (release-1.7.0)
+-e6bf85694ae8352d77175c4c7d304946e018808c src/windows-build (monad/cc6afbeb-3/31)
+```