Remove redundant casts

src/kemal/exceptions.cr

@@ -8,7 +8,7 @@ module Kemal::Exceptions
 
   class RouteNotFound < Exception
     def initialize(context : HTTP::Server::Context)
-      super "Requested path: '#{context.request.override_method.as(String)}:#{context.request.path}' was not found."
+      super "Requested path: '#{context.request.override_method}:#{context.request.path}' was not found."
     end
   end
 

src/kemal/ext/context.cr

@@ -33,7 +33,7 @@ class HTTP::Server
     end
 
     def route
-      route_lookup.payload.as(Kemal::Route)
+      route_lookup.payload
     end
 
     def route_lookup

src/kemal/param_parser.cr

@@ -60,7 +60,7 @@ module Kemal
     private def parse_url
       if params = @request.url_params
         params.each do |key, value|
-          @url[key.as(String)] = unescape_url_param(value).as(String)
+          @url[key] = unescape_url_param(value)
         end
       end
     end
@@ -88,7 +88,7 @@ module Kemal
       case json = JSON.parse(body).raw
       when Hash
         json.each do |key, value|
-          @json[key.as(String)] = value.as(AllParamTypes)
+          @json[key] = value.as(AllParamTypes)
         end
       when Array
         @json["_json"] = json