The syntax to use codefences is with backticks. If you provide the language after the first block of backticks, github will automatically put that in decent syntax highlighting. So, A simple code fence with AL code, can simply be done by:
```al
procedure ALGuidelinesRock()
var
Customer: Record Customer;
begin
Customer.Get('10000');
Customer.Name := 'waldo';
Customer.Modify(true);
end;
```
Results in:
procedure ALGuidelinesRock()
var
Customer: Record Customer;
begin
Customer.Get('10000');
Customer.Name :='waldo';
Customer.Modify(true);
end;