Rework fixers to decide what to use and move dehtmlify process in them.

Added githubv fixer.

fixers/github_com.go

@@ -0,0 +1,21 @@
+package fixers
+
+import (
+	"log/slog"
+
+	"github.com/mmcdole/gofeed"
+	"github.com/prodigeris/html2text"
+)
+
+func githubFixer(item *gofeed.Item) (string, string) {
+	plainTextBody, err := html2text.FromString(item.Content, html2text.Options{
+		PrettyTables: true,
+	})
+	if err != nil {
+		slog.Error("Failed to de-HTMLify github body!", "error", err.Error())
+
+		return item.Title, item.Content
+	}
+
+	return item.Title, plainTextBody
+}