[docs] Fix typo in blobstore.proto comment

[vpnda]

No description provided.

[aspect-workflows]

Test

28 test targets passed

Targets

//pkg/auth:auth_test [k8-fastbuild]                                                           964ms
//pkg/blobstore/buffer:buffer_test [k8-fastbuild]                                             70ms
//pkg/blobstore/completenesschecking:completenesschecking_test [k8-fastbuild]                 60ms
//pkg/blobstore/grpcclients:grpcclients_test [k8-fastbuild]                                   272ms
//pkg/blobstore/grpcservers:grpcservers_test [k8-fastbuild]                                   174ms
//pkg/blobstore/local:local_test [k8-fastbuild]                                               152ms
//pkg/blobstore/mirrored:mirrored_test [k8-fastbuild]                                         69ms
//pkg/blobstore/readcaching:readcaching_test [k8-fastbuild]                                   61ms
//pkg/blobstore/readfallback:readfallback_test [k8-fastbuild]                                 62ms
//pkg/blobstore/replication:replication_test [k8-fastbuild]                                   122ms
//pkg/blobstore/sharding/integration:integration_test [k8-fastbuild]                          91ms
//pkg/blobstore/sharding/legacy:legacy_test [k8-fastbuild]                                    455ms
//pkg/blobstore/sharding:sharding_test [k8-fastbuild]                                         811ms
//pkg/blobstore:blobstore_test [k8-fastbuild]                                                 125ms
//pkg/blockdevice:blockdevice_test [k8-fastbuild]                                             76ms
//pkg/builder:builder_test [k8-fastbuild]                                                     60ms
//pkg/capabilities:capabilities_test [k8-fastbuild]                                           59ms
//pkg/digest:digest_test [k8-fastbuild]                                                       65ms
//pkg/filesystem/path:path_test [k8-fastbuild]                                                138ms
//pkg/filesystem:filesystem_test [k8-fastbuild]                                               148ms
//pkg/grpc:grpc_test [k8-fastbuild]                                                           83ms
//pkg/http/server:server_test [k8-fastbuild]                                                  69ms
//pkg/jmespath:jmespath_test [k8-fastbuild]                                                   482ms
//pkg/jwt:jwt_test [k8-fastbuild]                                                             118ms
//pkg/otel:otel_test [k8-fastbuild]                                                           139ms
//pkg/prometheus:prometheus_test [k8-fastbuild]                                               113ms
//pkg/util:util_test [k8-fastbuild]                                                           254ms
//pkg/x509:x509_test [k8-fastbuild]                                                           61ms

Total test execution time was 5s. 2 tests (6.7%) were fully cached saving 135ms.