- More code cleanup and codestyle updates

- Fixed some possible nullref exceptions
- Methods signatures now have up to 3 parameters before breakaing down each parameter in a separate line
- Method invocations have the same rule, except the first parameter will be in the same line as the invocation to prevent some ugliness when passing lambas as arguments
- Applied many more codestyles
- Extensions folder fully reformatted

src/NadekoBot/Modules/Xp/Xp.cs

@@ -51,7 +51,7 @@ public partial class Xp : NadekoModule<XpService>
     {
         page--;
 
-        if (page < 0 || page > 100)
+        if (page is < 0 or > 100)
             return Task.CompletedTask;
 
         var allRewards = _service.GetRoleRewards(ctx.Guild.Id)