chore: fix typo in RewardBand description (#2234)

Co-authored-by: Unique Divine <[email protected]>

Author: mdqst

proto/nibiru/oracle/v1/oracle.proto

@@ -21,7 +21,7 @@ message Params {
     (gogoproto.customtype) = "github.com/cosmos/cosmos-sdk/types.Dec",
     (gogoproto.nullable) = false
   ];
-  // RewardBand defines a maxium divergence that a price vote can have from the
+  // RewardBand defines a maximum divergence that a price vote can have from the
   // weighted median in the ballot. If a vote lies within the valid range
   // defined by:
   //	μ := weightedMedian,