mmaprototype: fix typo

Author: tbg

pkg/kv/kvserver/allocator/mmaprototype/store_load_summary.go

@@ -10,7 +10,7 @@ import "github.com/cockroachdb/redact"
 // A storeLoadSummary is a classification of a store's load relative to the mean
 // load across a set of permissible stores (often, all that satisfy the
 // constraints for a given range). Sources and targets are primarily picked
-// based on the store- and node level load summaries contained in this struct.
+// based on the store and node level load summaries contained in this struct.
 type storeLoadSummary struct {
 	worstDim                                               LoadDimension // for logging only
 	sls                                                    loadSummary