Update Kemal to 1.6.0 and remove Kilt (#5120)

src/ext/kemal_content_for.cr

@@ -1,16 +0,0 @@
-# Overrides for Kemal's `content_for` macro in order to keep using
-# kilt as it was before Kemal v1.1.1 (Kemal PR #618).
-
-require "kemal"
-require "kilt"
-
-macro content_for(key, file = __FILE__)
-  %proc = ->() {
-    __kilt_io__ = IO::Memory.new
-    {{ yield }}
-    __kilt_io__.to_s
-  }
-
-  CONTENT_FOR_BLOCKS[{{key}}] = Tuple.new {{file}}, %proc
-  nil
-end

src/ext/kemal_static_file_handler.cr

@@ -71,7 +71,7 @@ def send_file(env : HTTP::Server::Context, file_path : String, data : Slice(UInt
   filesize = data.bytesize
   attachment(env, filename, disposition)
 
-  Kemal.config.static_headers.try(&.call(env.response, file_path, filestat))
+  Kemal.config.static_headers.try(&.call(env, file_path, filestat))
 
   file = IO::Memory.new(data)
   if env.request.method == "GET" && env.request.headers.has_key?("Range")

src/invidious.cr

@@ -17,10 +17,8 @@
 require "digest/md5"
 require "file_utils"
 
-# Require kemal, kilt, then our own overrides
+# Require kemal, then our own overrides
 require "kemal"
-require "kilt"
-require "./ext/kemal_content_for.cr"
 require "./ext/kemal_static_file_handler.cr"
 
 require "http_proxy"
@@ -226,8 +224,8 @@ error 500 do |env, ex|
   error_template(500, ex)
 end
 
-static_headers do |response|
-  response.headers.add("Cache-Control", "max-age=2629800")
+static_headers do |env|
+  env.response.headers.add("Cache-Control", "max-age=2629800")
 end
 
 # Init Kemal

src/invidious/helpers/macros.cr

@@ -55,12 +55,11 @@ macro templated(_filename, template = "template", navbar_search = true)
   {{ layout = "src/invidious/views/" + template + ".ecr" }}
 
   __content_filename__ = {{filename}}
-  content = Kilt.render({{filename}})
-  Kilt.render({{layout}})
+  render {{filename}}, {{layout}}
 end
 
 macro rendered(filename)
-  Kilt.render("src/invidious/views/#{{{filename}}}.ecr")
+  render("src/invidious/views/#{{{filename}}}.ecr")
 end
 
 # Similar to Kemals halt method but works in a