Pull request: 4970-error-415

Updates #4970.

Squashed commit of the following:

commit 10365d9c8474e9d9735f581fb32b2892b2153cc4
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Fri Sep 30 14:23:06 2022 +0300

    all: imp docs, names

commit cff1103a0618a6430dc91e7e018febbf313c12ba
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Fri Sep 30 14:02:38 2022 +0300

    home: imp content-type check

internal/aghhttp/aghhttp.go

@@ -33,7 +33,7 @@ func OK(w http.ResponseWriter) {
 // Error writes formatted message to w and also logs it.
 func Error(r *http.Request, w http.ResponseWriter, code int, format string, args ...any) {
 	text := fmt.Sprintf(format, args...)
-	log.Error("%s %s: %s", r.Method, r.URL, text)
+	log.Error("%s %s %s: %s", r.Method, r.Host, r.URL, text)
 	http.Error(w, text, code)
 }