consensus/clique: fix struct tags for status API (ethereum#20316)

Also unexport the status struct.

consensus/clique/api.go

@@ -120,17 +120,17 @@ func (api *API) Discard(address common.Address) {
 	delete(api.clique.proposals, address)
 }
 
-type Status struct {
+type status struct {
 	InturnPercent float64                `json:"inturnPercent"`
-	SigningStatus map[common.Address]int `json:"sealerActivity""`
+	SigningStatus map[common.Address]int `json:"sealerActivity"`
 	NumBlocks     uint64                 `json:"numBlocks"`
 }
 
 // Status returns the status of the last N blocks,
 // - the number of active signers,
 // - the number of signers,
 // - the percentage of in-turn blocks
-func (api *API) Status() (*Status, error) {
+func (api *API) Status() (*status, error) {
 	var (
 		numBlocks = uint64(64)
 		header    = api.chain.CurrentHeader()
@@ -169,7 +169,7 @@ func (api *API) Status() (*Status, error) {
 		}
 		signStatus[sealer]++
 	}
-	return &Status{
+	return &status{
 		InturnPercent: float64((100 * optimals)) / float64(numBlocks),
 		SigningStatus: signStatus,
 		NumBlocks:     numBlocks,