Change Details

* Update feature list * Be more positive about the state and quality of the library * Mention ECDSA key operations explicitly in short library description * Say "secret key" instead of "private key * Define "experimental" Co-Authored-By: Gregory Maxwell <greg@xiph.org> This is a backport of libsecp256k1 PR703

* Update feature list * Be more positive about the state and quality of the library * Mention ECDSA key operations explicitly in short library description * Say "secret key" instead of "private key * Define "experimental" Co-Authored-By: Gregory Maxwell <greg@xiph.org> This is a backport of libsecp256k1 PR703 Depends on D5377

* Update feature list * Be more positive about the state and quality of the library * Mention ECDSA key operations explicitly in short library description * Say "secret key" instead of "private key * Define "experimental" Co-Authored-By: Gregory Maxwell <greg@xiph.org> This is a backport of libsecp256k1 PR703 Depends on D5377