feat(scraper): add scraper rule for vnexpress.net

internal/reader/scraper/rules.go

@@ -52,6 +52,7 @@ var predefinedRules = map[string]string{
 	"turnoff.us":           "article.post-content",
 	"universfreebox.com":   "#corps_corps",
 	"version2.dk":          "section.body",
+	"vnexpress.net":        ".detail-new p.description, article.fck_detail",
 	"wdwnt.com":            "div.entry-content",
 	"webtoons.com":         ".viewer_img,p.author_text",
 	"wired.com":            "main figure, article",