include: remove WARN_UNUSED_RESULT for functions always returning 1 #1659

1. 
   jonasnick commented at 9:37 am on March 13, 2025: contributor

   This makes the usage of the atribute consistent. In the musig and ellswift module, functions that return 1 always already don’t have the WARN_UNUSED_RESULT attribute. In secp256k1.h and the extrakeys module, this has only been the case partially.

   In all cases where this was removed, the function only returns 0 if the illegal callback has been called.

   Fixes #1379

2. include: remove WARN_UNUSED_RESULT for functions always returning 1

   This makes the usage of the atribute consistent. In the musig and ellswift
   module, functions that return 1 always already don't have the WARN_UNUSED_RESULT
   attribute. In secp256k1.h and the extrakeys module, this has only been the case
   partially.
   
   In all cases where this was removed, the function only returns 0 if the illegal
   callback has been called.

   1b6e081538
3. jonasnick added the label needs-changelog on Mar 13, 2025
4. real-or-random added the label assurance on Mar 13, 2025
5. real-or-random added the label refactor/smell on Mar 13, 2025
6. real-or-random approved
7. 
   real-or-random commented at 10:03 am on March 13, 2025: contributor

   utACK https://github.com/bitcoin-core/secp256k1/pull/1659/commits/1b6e081538cc9a171157ec858c4aac19deb7d6cc
8. 
   sipa commented at 12:15 pm on March 13, 2025: contributor

   utACK 1b6e081538cc9a171157ec858c4aac19deb7d6cc
9. real-or-random merged this on Mar 13, 2025
10. real-or-random closed this on Mar 13, 2025

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11. hebasto referenced this in commit dd59896431 on Mar 17, 2025
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16. josibake referenced this in commit 65e455e102 on Apr 8, 2025
17. hebasto referenced this in commit 017ff1c67c on May 8, 2025
18. josibake referenced this in commit 6ddb83d3da on May 12, 2025
19. hebasto referenced this in commit c31fcaaad3 on May 13, 2025
20. josibake referenced this in commit 8839cb10d8 on May 13, 2025
21. fanquake referenced this in commit 8309a9747a on May 13, 2025
22. josibake referenced this in commit 497f1536ef on May 14, 2025
23. vmta referenced this in commit 3a0314c68f on May 22, 2025
24. josibake referenced this in commit bb0dc6d75c on Jul 10, 2025
25. real-or-random referenced this in commit 6037833c9e on Jul 21, 2025
26. fanquake removed the label needs-changelog on Jul 29, 2025
27. 
    fanquake commented at 10:26 am on July 29, 2025: member

    Changelog was added in #1702. Dropping “needs-changelog”.

Contributors
jonasnick real-or-random sipa fanquake

Labels
assurance tweak/refactor