doc: rpc: improve getmininginfo help text

- The reserved weight of the coinbase transaction is an estimate and
  may not reflect the exact value; it can be lower.

- It should be clear that `currentblockweight` includes the reserved coinbase transaction weight.
  whereas `currentblocktx` does not account for the coinbase transaction count.

- Also clarify `m_last_block_num_txs` and `m_last_block_weight`

Author: ismaelsadeeq

src/node/miner.h

@@ -176,7 +176,9 @@ class BlockAssembler
     /** Construct a new block template */
     std::unique_ptr<CBlockTemplate> CreateNewBlock();
 
+    /** The number of transactions in the last assembled block (excluding coinbase transaction) */
     inline static std::optional<int64_t> m_last_block_num_txs{};
+    /** The weight of the last assembled block (including reserved weight for block header, txs count and coinbase tx) */
     inline static std::optional<int64_t> m_last_block_weight{};
 
 private:

src/rpc/mining.cpp

@@ -419,8 +419,8 @@ static RPCHelpMan getmininginfo()
                     RPCResult::Type::OBJ, "", "",
                     {
                         {RPCResult::Type::NUM, "blocks", "The current block"},
-                        {RPCResult::Type::NUM, "currentblockweight", /*optional=*/true, "The block weight of the last assembled block (only present if a block was ever assembled)"},
-                        {RPCResult::Type::NUM, "currentblocktx", /*optional=*/true, "The number of block transactions of the last assembled block (only present if a block was ever assembled)"},
+                        {RPCResult::Type::NUM, "currentblockweight", /*optional=*/true, "The block weight (including reserved weight for block header, txs count and coinbase tx) of the last assembled block (only present if a block was ever assembled)"},
+                        {RPCResult::Type::NUM, "currentblocktx", /*optional=*/true, "The number of block transactions (excluding coinbase) of the last assembled block (only present if a block was ever assembled)"},
                         {RPCResult::Type::STR_HEX, "bits", "The current nBits, compact representation of the block difficulty target"},
                         {RPCResult::Type::NUM, "difficulty", "The current difficulty"},
                         {RPCResult::Type::STR_HEX, "target", "The current target"},