Remove deprecated secp256k1_schnorrsig_sign alias #1776

1. 
   theStack commented at 3:27 pm on November 26, 2025: contributor

   This function has been deprecated since the rename to _schnorrsig_sign32 more than three and a half years ago (see PR #1089, commit 99e6568fc6), before the first official release 0.2.0. Removing it should be fine by now.
2. Remove deprecated `secp256k1_schnorrsig_sign` alias

   This function has been deprecated since the rename to `_schnorrsig_sign32`
   more than three and a half years ago (see PR #1089, commit 99e6568fc6),
   before the first official release 0.2.0. Removing it should be fine by now.

   405e29b6fd
3. theStack force-pushed on Nov 26, 2025
4. real-or-random added the label needs-changelog on Nov 27, 2025
5. real-or-random added the label tweak/refactor on Nov 27, 2025
6. real-or-random removed the label needs-changelog on Nov 27, 2025
7. real-or-random approved
8. 
   real-or-random commented at 4:24 pm on November 27, 2025: contributor

   utACK 405e29b6fd76f59b16091059c9ab4a4fd2f08bf1

   This change is fine, but it’s not at all necessary or urgent, so we may want to postpone this until we have more reason to do a breaking release.

Contributors
theStack real-or-random

Labels
tweak/refactor