- 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/CustomReactions/CustomReactions.cs

@@ -95,7 +95,7 @@ public class CustomReactions : NadekoModule<CustomReactionsService>
                               + (string.IsNullOrWhiteSpace(cr.Reactions)
                                   ? string.Empty
                                   : " // " + string.Join(" ", cr.GetReactions())))
-                .JoinWith('\n');
+                .Join('\n');
 
             return _eb.Create().WithOkColor()
                 .WithTitle(GetText(strs.custom_reactions))

src/NadekoBot/Modules/CustomReactions/Extensions/CustomReactionExtensions.cs

@@ -33,8 +33,8 @@ public static class CustomReactionExtensions
         var rep = new ReplacementBuilder()
             .WithDefault(ctx.Author, ctx.Channel, (ctx.Channel as ITextChannel)?.Guild as SocketGuild, client)
             .WithOverride("%target%", () => canMentionEveryone
-                ? ctx.Content.Substring(substringIndex).Trim()
-                : ctx.Content.Substring(substringIndex).Trim().SanitizeMentions(true))
+                ? ctx.Content[substringIndex..].Trim()
+                : ctx.Content[substringIndex..].Trim().SanitizeMentions(true))
             .Build();
 
         var text = SmartText.CreateFrom(cr.Response);
@@ -69,11 +69,7 @@ public static class CustomReactionExtensions
     private static bool isValidWordDivider(this in ReadOnlySpan<char> str, int index)
     {
         var ch = str[index];
-        if (ch is >= 'a' and <= 'z')
-            return false;
-        if (ch is >= 'A' and <= 'Z')
-            return false;
-        if (ch is >= '1' and <= '9')
+        if (ch is >= 'a' and <= 'z' or >= 'A' and <= 'Z' or >= '1' and <= '9')
             return false;
 
         return true;

src/NadekoBot/Modules/CustomReactions/Services/CustomReactionsService.cs

@@ -713,7 +713,7 @@ public sealed class CustomReactionsService : IEarlyBehavior, IReadyExecutor
                 {
                     GuildId = guildId,
                     Response = cr.Res,
-                    Reactions = cr.React?.JoinWith("@@@"),
+                    Reactions = cr.React?.Join("@@@"),
                     Trigger = trigger,
                     AllowTarget = cr.At,
                     ContainsAnywhere = cr.Ca,