Update docs regarding compilation

Author: ThomasFarstrike

docs/os-development/compiling.md

@@ -3,7 +3,7 @@
 Clone the repositories:
 
 ```
-git clone --recurse-submodules https://github.com/MicroPythonOS/MicroPythonOS.git
+git clone --recurse-submodules --depth 1 --shallow-submodules https://github.com/MicroPythonOS/MicroPythonOS.git
 cd MicroPythonOS/
 ```
 
@@ -18,7 +18,8 @@ But if you need to save on bandwidth and time, you can instead do the following,
 ```
 cd MicroPythonOS/
 git submodule foreach --recursive 'git clean -f; git checkout .'
-git pull --recurse-submodules
+git pull --depth 1
+git submodule update --init --depth 1
 ```
 
 ## Compile the code

docs/os-development/running-on-desktop.md

@@ -4,14 +4,7 @@
 
     If you built from source, you will already have a local clone that contains it.
 
-    If you used a pre-built binary, then you need to get a local clone and change into that directory with:
-
-    <pre>
-    ```
-    git clone --recurse-submodules https://github.com/MicroPythonOS/MicroPythonOS.git
-    cd MicroPythonOS/
-    ```
-    </pre>
+    If you used a pre-built binary, you can download the accompanying "Source code" zip from the [releases page](https://github.com/MicroPythonOS/MicroPythonOS/releases) and extract the internal_filesystem/ folder from it.
 
 2. **Make sure you have the software**