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)

models/git/branches.go

@@ -363,7 +363,7 @@ func updateApprovalWhitelist(ctx context.Context, repo *repo_model.Repository, c
 		whitelist = append(whitelist, userID)
 	}
 
-	return
+	return whitelist, err
 }
 
 // updateUserWhitelist checks whether the user whitelist changed and returns a whitelist with
@@ -392,7 +392,7 @@ func updateUserWhitelist(ctx context.Context, repo *repo_model.Repository, curre
 		whitelist = append(whitelist, userID)
 	}
 
-	return
+	return whitelist, err
 }
 
 // updateTeamWhitelist checks whether the team whitelist changed and returns a whitelist with
@@ -415,7 +415,7 @@ func updateTeamWhitelist(ctx context.Context, repo *repo_model.Repository, curre
 		}
 	}
 
-	return
+	return whitelist, err
 }
 
 // DeleteProtectedBranch removes ProtectedBranch relation between the user and repository.
@@ -539,7 +539,7 @@ func FindRenamedBranch(repoID int64, from string) (branch *RenamedBranch, exist
 	}
 	exist, err = db.GetEngine(db.DefaultContext).Get(branch)
 
-	return
+	return branch, exist, err
 }
 
 // RenameBranch rename a branch

models/git/commit_status.go

@@ -74,7 +74,7 @@ func upsertCommitStatusIndex(ctx context.Context, repoID int64, sha string) (err
 	default:
 		return fmt.Errorf("database type not supported")
 	}
-	return
+	return err
 }
 
 // GetNextCommitStatusIndex retried 3 times to generate a resource index