Minor fixes to documentation and formatting

Co-authored-by: Daira Hopwood <daira@jacaranda.org>

src/chain.h

@@ -270,7 +270,7 @@ public:
     CAmount nOrchardValue;
 
     //! (memory only) Total value held by the Orchard circuit up to and including this block.
-    //! Will be std::nullopt if nChainTx is zero.
+    //! Will be std::nullopt if and only if nChainTx is zero.
     std::optional<CAmount> nChainOrchardValue;
 
     //! Root of the Sapling commitment tree as of the end of this block.

src/main.cpp

@@ -2818,7 +2818,7 @@ bool ConnectBlock(const CBlock& block, CValidationState& state, CBlockIndex* pin
         if (pindex->nChainOrchardValue) {
             if (*pindex->nChainOrchardValue < 0) {
                 return state.DoS(100, error("ConnectBlock(): turnstile violation in Orchard shielded value pool"),
-                                REJECT_INVALID, "turnstile-violation-orchard");
+                                 REJECT_INVALID, "turnstile-violation-orchard");
             }
         }
     }