Updating all pxt.microbit.org reference to makecode.microbit.org (#460)

docs/device/usb/mac-chrome.md

@@ -34,7 +34,7 @@ it appears as a new drive under Devices.
 
 ## Step 2: Download your program
 
-1. Open your project on [pxt.microbit.org](https://pxt.microbit.org)
+1. Open your project on @homeurl@
 2. Click **Download**
 3. When prompted, choose to **save** the compiled file onto your computer. The
    prompt will be different depending on which browser you are using, or

docs/device/usb/mac-firefox.md

@@ -34,7 +34,7 @@ it appears as a new drive under Devices.
 
 ## Step 2: Download your program
 
-1. Open your project on [pxt.microbit.org](https://pxt.microbit.org)
+1. Open your project on @homeurl@
 2. Click **Download**
 3. When prompted, choose to **save** the compiled file onto your computer. The
    prompt will be different depending on which browser you are using, or

docs/device/usb/mac-safari.md

@@ -34,7 +34,7 @@ it appears as a new drive under Devices.
 
 ## Step 2: Download your program
 
-1. Open your project on [pxt.microbit.org](https://pxt.microbit.org)
+1. Open your project on @homeurl@
 2. Click **Download**
 3. When prompted, choose to **save** the compiled file onto your computer. The
    prompt will be different depending on which browser you are using, or

docs/device/usb/windows-chrome.md

@@ -43,7 +43,7 @@ You only need to do this once.
 
 ## Step 3: Download your program
 
-1. Open your project on [pxt.microbit.org](https://pxt.microbit.org)
+1. Open your project on @homeurl@
 2. Click **Download**
 3. If you did Step 2 above, Chrome will ask where to save the `.hex` file,
     so save it into the `MICROBIT` drive.

docs/device/usb/windows-edge.md

@@ -36,7 +36,7 @@ it appears as a new drive under Devices.
 
 ## Step 2: Download your program
 
-1. Open your project on [pxt.microbit.org](https://pxt.microbit.org)
+1. Open your project on @homeurl@
 2. Click **Download**
 3. When prompted, choose to **save** the compiled file onto your computer. The
    prompt will be different depending on which browser you are using, or

docs/device/usb/windows-firefox.md

@@ -36,7 +36,7 @@ it appears as a new drive under Devices.
 
 ## Step 2: Download your program
 
-1. Open your project on [pxt.microbit.org](https://pxt.microbit.org)
+1. Open your project on @homeurl@
 2. Click **Download**
 3. When prompted, choose to **save** the compiled file onto your computer. The
    prompt will be different depending on which browser you are using, or

docs/device/usb/windows-ie.md

@@ -35,7 +35,7 @@ it appears as a new drive under Devices.
 
 ## Step 2: Download your program
 
-1. Open your project on [pxt.microbit.org](https://pxt.microbit.org)
+1. Open your project on @homeurl@
 2. Click **Download**
 3. When prompted, choose to **save** the compiled file onto your computer. The
    prompt will be different depending on which browser you are using, or