8c7c5e7394 Remove deprecated code (Tobin C. Harding)
e779e5dc05 doc: Use add_tweak in example code (Tobin C. Harding)
eedbd0b7e4 secp256k1-sys: Remove deprecated code (Tobin C. Harding)
Pull request description:
Remove deprecated code from `secp256k1-sys` and `secp256k1`.
ACKs for top commit:
apoelstra:
ACK 8c7c5e7394
Tree-SHA512: 830d4459cf21fba98e75e1c099c96316c9db1c1fb87dd28343cea066544ac8568685ec9fc85969caee3d35014f64c3f42b5a5afbf4f4d16221a57a204e6a3524