change formatting

input examples are now given as

```bash
input $ARG1
```

While outputs use md's '> ' sign as a quote.

vision/qrencode.md

@@ -5,9 +5,13 @@ tags: [ "Documentation", "vision" ]
 
 Make a QR Code image:
 
-> qrencode 'https://play.google.com/store/apps/details?id=org.briarproject.briar.android' -o qr_briar.png
+```bash
+qrencode 'https://play.google.com/store/apps/details?id=org.briarproject.briar.android' -o qr_briar.png
+```
 
 Make a QR Coded message in the terminal:
 
-> qrencode -t ansi "Hello World"
+```bash
+qrencode -t ansi "Hello World"
+```