Replace prazdnikisegodnyaru with celebratoday, small underhood fixes

- Replace prazdnikisegodnyaru with celebratoday as first is banned in Russia
- Update .golangci.yml rule set
- Megatons of fixes for linter
- Update README.md

internal/bunicomic/bunicomic.go

@@ -1,3 +1,4 @@
+// Package bunicomic implements client for bunicomic.com service.
 package bunicomic
 
 import (
@@ -48,13 +49,13 @@ func APIClient(cfg *config.MyConfig) (string, error) {
 		if n.Type == html.ElementNode && n.Data == "meta" {
 			for _, meta := range n.Attr {
 				if meta.Key == "content" {
-					// adds a new link entry when the attribute matches
+					// Adds a new link entry when the attribute matches.
 					metaTags = append(metaTags, meta.Val)
 				}
 			}
 		}
 
-		// traverses the HTML of the webpage from the first child node
+		// Traverses the HTML of the webpage from the first child node.
 		for c := n.FirstChild; c != nil; c = c.NextSibling {
 			meta(c)
 		}