Trivial error message fix.

Co-authored-by: str4d <thestr4d@gmail.com>

src/miner.cpp

@@ -220,7 +220,7 @@ public:
 
         if (!success) {
             librustzcash_sapling_proving_ctx_free(ctx);
-            throw new std::runtime_error("An error occurrec computing the binding signature.");
+            throw new std::runtime_error("An error occurred computing the binding signature.");
         }
     }