Swift: Add swift-further-reading.rst

Author: geoffw0

docs/codeql/reusables/swift-further-reading.rst

@@ -0,0 +1,4 @@
+- `CodeQL queries for Swift <https://github.com/github/codeql/tree/main/swift/ql/src/queries>`__
+- `Example queries for Swift <https://github.com/github/codeql/tree/main/swift/ql/examples>`__
+- `CodeQL library reference for Swift <https://codeql.github.com/codeql-standard-libraries/swift/>`__
+