Update CONTRIBUTING.md

Author: kislyuk

CONTRIBUTING.md

@@ -15,9 +15,10 @@ Contributions via [issues](https://github.com/XML-Security/implementations/issue
 
 # Participating
 
-If you wish to become a member of the [XML Security](https://github.com/XML-Security) project, please open an issue or email
-project members directly. Experts in the aforementioned security-related XML standards and active contributors to
-implementations are invited to join.
+If you wish to become a member of the [XML Security](https://github.com/XML-Security) project, please open an issue in this
+repository or email project members directly. Experts in the aforementioned security-related XML standards and active
+contributors to implementations are invited to join.
 
-If you wish to transfer a library or implementation that you maintain under this project, please open an issue or email
-project members directly. Open source libraries and implementations that are actively maintained are invited to join.
+If you wish to transfer a library or implementation that you maintain under this project, please open an issue in this
+repository or email project members directly. Open source libraries and implementations that are actively maintained are
+invited to join.