Merge bitcoin/bitcoin#24084: doc: add information about status code 404 for some endpoints (rest)

0811cbf doc: add info about status code 404 for some rest endpoints (brunoerg)

Pull request description:

  This PR adds an explanation about status code 404 for 2 endpoints (`/rest/tx/ `and `/rest/blockhashbyheight/`) in`REST-interface.md`. There are other endpoints that already cover it.

ACKs for top commit:
  [deleted]:
    reACK bitcoin/bitcoin@0811cbf
  shaavan:
    ACK 0811cbf

Tree-SHA512: a01ac6653f706b7a7e4a4679a2b81e448381f31460ac4bcfc179af6186401cffae7b49a82f3a52c89e556acd5c16c159ce752c7a678177900ddf2e4e5c72fe6b

Author: fanquake

doc/REST-interface.md

@@ -31,6 +31,7 @@ Supported API
 `GET /rest/tx/<TX-HASH>.<bin|hex|json>`
 
 Given a transaction hash: returns a transaction in binary, hex-encoded binary, or JSON formats.
+Responds with 404 if the transaction doesn't exist.
 
 By default, this endpoint will only search the mempool.
 To query for a confirmed transaction, enable the transaction index via "txindex=1" command line / configuration option.
@@ -76,6 +77,7 @@ Responds with 404 if the block doesn't exist.
 `GET /rest/blockhashbyheight/<HEIGHT>.<bin|hex|json>`
 
 Given a height: returns hash of block in best-block-chain at height provided.
+Responds with 404 if block not found.
 
 #### Chaininfos
 `GET /rest/chaininfo.json`