Fix golangci-lint warnings (#17598 et al) (#17668)

Backport #17598 
Backport #17606 
Backport #17608 
Backport #17609

- Since https://gitea.com/gitea/test-env/pulls/10 the golangci-lint has been upgraded and is erroring about new warnings in the code, this PR fixes those warnings.

modules/markup/common/footnote.go

@@ -126,7 +126,7 @@ type Footnote struct {
 func (n *Footnote) Dump(source []byte, level int) {
 	m := map[string]string{}
 	m["Index"] = fmt.Sprintf("%v", n.Index)
-	m["Ref"] = fmt.Sprintf("%s", n.Ref)
+	m["Ref"] = string(n.Ref)
 	m["Name"] = fmt.Sprintf("%v", n.Name)
 	ast.DumpHelper(n, source, level, m, nil)
 }