Add more linters to improve code readability (#19989)

Add nakedret, unconvert, wastedassign, stylecheck and nolintlint linters to improve code readability

- nakedret - https://github.com/alexkohler/nakedret - nakedret is a Go static analysis tool to find naked returns in functions greater than a specified function length.
- unconvert - https://github.com/mdempsky/unconvert - Remove unnecessary type conversions
- wastedassign - https://github.com/sanposhiho/wastedassign -  wastedassign finds wasted assignment statements.
- notlintlint -  Reports ill-formed or insufficient nolint directives
- stylecheck - https://staticcheck.io/docs/checks/#ST - keep style consistent
  - excluded: [ST1003 - Poorly chosen identifier](https://staticcheck.io/docs/checks/#ST1003) and [ST1005 - Incorrectly formatted error string](https://staticcheck.io/docs/checks/#ST1005)

modules/convert/convert.go

@@ -257,7 +257,7 @@ func ToHook(repoLink string, w *webhook.Webhook) *api.Hook {
 
 	return &api.Hook{
 		ID:      w.ID,
-		Type:    string(w.Type),
+		Type:    w.Type,
 		URL:     fmt.Sprintf("%s/settings/hooks/%d", repoLink, w.ID),
 		Active:  w.IsActive,
 		Config:  config,

modules/convert/issue.go

@@ -123,7 +123,7 @@ func ToTrackedTime(t *issues_model.TrackedTime) (apiT *api.TrackedTime) {
 	if t.User != nil {
 		apiT.UserName = t.User.Name
 	}
-	return
+	return apiT
 }
 
 // ToStopWatches convert Stopwatch list to api.StopWatches