fix typo (#2509)

Signed-off-by: arthur yang <yang_yapo@126.com>

pkg/store/storepb/rpc.proto

@@ -21,7 +21,7 @@ option (gogoproto.goproto_unkeyed_all) = false;
 option (gogoproto.goproto_unrecognized_all) = false;
 option (gogoproto.goproto_sizecache_all) = false;
 
-/// Store reprents API against instance that stores XOR encoded values with label set metadata (e.g Prometheus metrics).
+/// Store represents API against instance that stores XOR encoded values with label set metadata (e.g Prometheus metrics).
 service Store {
   /// Info returns meta information about a store e.g labels that makes that store unique as well as time range that is
   /// available.
@@ -43,7 +43,7 @@ service Store {
   rpc LabelValues(LabelValuesRequest) returns (LabelValuesResponse);
 }
 
-/// WriteableStore reprents API against instance that stores XOR encoded values with label set metadata (e.g Prometheus metrics).
+/// WriteableStore represents API against instance that stores XOR encoded values with label set metadata (e.g Prometheus metrics).
 service WriteableStore {
   // WriteRequest allows you to write metrics to this store via remote write
   rpc RemoteWrite(WriteRequest) returns (WriteResponse) {}