Merge bitcoin/bitcoin#26603: doc: CalculateSequenceLocks: prevHeights entries are set to 0, not removed

f537127 doc: fix: prevHeights entries are set to 0, not removed (stickies-v)

Pull request description:

  In [`CalculateSequenceLocks`](https://github.com/bitcoin/bitcoin/blob/a035b6a0c418d0b720707df69559028bd662fa70/src/consensus/tx_verify.h#L69) no items are removed from `prevHeights`, they are just set to 0:

  https://github.com/bitcoin/bitcoin/blob/a035b6a0c418d0b720707df69559028bd662fa70/src/consensus/tx_verify.cpp#L69-L73

  This PR updates the docs to reflect the actual implementation. Seems to have been wrongly documented since introduction in #7184 already ([implementation](https://github.com/bitcoin/bitcoin/pull/7184/files#diff-34d21af3c614ea3cee120df276c9c4ae95053830d7f1d3deaf009a4625409ad2R742-R749) and [documentation](https://github.com/bitcoin/bitcoin/pull/7184/files#diff-34d21af3c614ea3cee120df276c9c4ae95053830d7f1d3deaf009a4625409ad2R712-R713))

ACKs for top commit:
  hebasto:
    ACK f537127

Tree-SHA512: 3661501660f6832b2116fd83466ffe95a60b341c14cb09a37489e2a587bea3290b0528690120a0f644c3eea02177aa1fb8968258482fa43b0303e016abb17418

Author: glozow

src/consensus/tx_verify.h

@@ -63,8 +63,8 @@ bool IsFinalTx(const CTransaction &tx, int nBlockHeight, int64_t nBlockTime);
 /**
  * Calculates the block height and previous block's median time past at
  * which the transaction will be considered final in the context of BIP 68.
- * Also removes from the vector of input heights any entries which did not
- * correspond to sequence locked inputs as they do not affect the calculation.
+ * For each input that is not sequence locked, the corresponding entries in
+ * prevHeights are set to 0 as they do not affect the calculation.
  */
 std::pair<int, int64_t> CalculateSequenceLocks(const CTransaction &tx, int flags, std::vector<int>& prevHeights, const CBlockIndex& block);