refactor: fix explicit type declarations (#67)

Explicit types where they can be easily inferred may add unnecessary verbosity for variables or parameters initialized to a number, string, or boolean

Co-authored-by: deepsource-autofix[bot] <62050782+deepsource-autofix[bot]@users.noreply.github.com>

Author: deepsource-autofix[bot]

src/core/Client.ts

@@ -42,7 +42,7 @@ export default class SuperClient<R extends boolean = boolean> extends Client<R>
   private readonly eventManager = EventManager;
 
   private _connectionCache: Collection<string, connectedList> = new Collection();
-  private _cachePopulated: boolean = false;
+  private _cachePopulated = false;
   private readonly scheduler = new Scheduler();
 
   readonly description = 'The only cross-server chatting bot you\'ll ever need.';