Pull request: all: fix lint and naming issues

Merge in DNS/adguard-home from 2276-fix-lint to master

Updates #2276.

Squashed commit of the following:

commit 433f44cc7b674a20ed60a9d29466ba888b3ef66e
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Mon Dec 7 14:14:28 2020 +0300

    querylog: improve code and documentation

commit 851df97d2a87de5e7180a502055ee6f1a6defdca
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Fri Dec 4 20:36:32 2020 +0300

    all: fix lint and naming issues

internal/stats/http.go

@@ -37,7 +37,13 @@ func (s *statsCtx) handleStats(w http.ResponseWriter, r *http.Request) {
 	}
 
 	w.Header().Set("Content-Type", "application/json")
-	w.Write(data)
+
+	_, err = w.Write(data)
+	if err != nil {
+		httpError(r, w, http.StatusInternalServerError, "json encode: %s", err)
+
+		return
+	}
 }
 
 type config struct {

internal/stats/stats.go

@@ -1,5 +1,5 @@
-// Module for managing statistics for DNS filtering server
-
+// Package stats provides units for managing statistics of the filtering DNS
+// server.
 package stats
 
 import (