Merge #1683: README: add link to musig example

8192109 README: add link to musig example, generalize module enabling hint (Sebastian Falbesoner)

Pull request description:

ACKs for top commit:
  real-or-random:
    ACK 8192109

Tree-SHA512: 9bfc7e59f0b6c6bacc591abe9835d1e6129e4daf286b91b35fad83ddf7d870a534d83ce2c27165ed8612f05695a5f15a3ef7bebbcbe63a5fe843d4c0617ebc9f

Author: real-or-random

README.md

@@ -151,8 +151,9 @@ Usage examples can be found in the [examples](examples) directory. To compile th
   * [Schnorr signatures example](examples/schnorr.c)
   * [Deriving a shared secret (ECDH) example](examples/ecdh.c)
   * [ElligatorSwift key exchange example](examples/ellswift.c)
+  * [MuSig2 Schnorr multi-signatures example](examples/musig.c)
 
-To compile the Schnorr signature and ECDH examples, you also need to configure with `--enable-module-schnorrsig` and `--enable-module-ecdh`.
+To compile the examples, make sure the corresponding modules are enabled.
 
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