- 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/Db/Models/FeedSub.cs

@@ -9,14 +9,10 @@ public class FeedSub : DbEntity
     public string Url { get; set; }
 
     public override int GetHashCode()
-    {
-        return Url.GetHashCode(StringComparison.InvariantCulture) ^ GuildConfigId.GetHashCode();
-    }
+        => Url.GetHashCode(StringComparison.InvariantCulture) ^ GuildConfigId.GetHashCode();
 
     public override bool Equals(object obj)
-    {
-        return obj is FeedSub s
-               && s.Url.ToLower() == Url.ToLower()
-               && s.GuildConfigId == GuildConfigId;
-    }
+        => obj is FeedSub s
+           && s.Url.ToLower() == Url.ToLower()
+           && s.GuildConfigId == GuildConfigId;
 }